diff --git a/testground/benchmark/benchmark/peer.py b/testground/benchmark/benchmark/peer.py
index f8b043b758..91adc5a88d 100644
--- a/testground/benchmark/benchmark/peer.py
+++ b/testground/benchmark/benchmark/peer.py
@@ -4,6 +4,7 @@
 from pathlib import Path
 from typing import List
 
+import jsonmerge
 from pydantic.json import pydantic_encoder
 
 from .cli import ChainCommand
@@ -133,41 +134,54 @@ def gen_genesis(
     print("genesis validated")
     return patch_json(
         leader_home / "config" / "genesis.json",
-        {
-            "consensus.params.block.max_gas": "163000000",
-            "app_state.evm.params.evm_denom": "basecro",
-            "app_state.feemarket.params.no_base_fee": True,
-            **genesis_patch,
-        },
+        jsonmerge.merge(
+            {
+                "consensus": {"params": {"block": {"max_gas": "163000000"}}},
+                "app_state": {
+                    "evm": {"params": {"evm_denom": "basecro"}},
+                    "feemarket": {"params": {"no_base_fee": True}},
+                },
+            },
+            genesis_patch,
+        ),
     )
 
 
 def patch_configs(home: Path, peers: str, config_patch: dict, app_patch: dict):
     default_config_patch = {
         "db_backend": "rocksdb",
-        "p2p.addr_book_strict": False,
-        "mempool.recheck": False,
-        "mempool.size": MEMPOOL_SIZE,
-        "consensus.timeout_commit": "1s",
-        "tx_index.indexer": "null",
+        "p2p": {"addr_book_strict": False},
+        "mempool": {
+            "recheck": False,
+            "size": MEMPOOL_SIZE,
+        },
+        "consensus": {"timeout_commit": "1s"},
+        "tx_index": {"indexer": "null"},
     }
     default_app_patch = {
         "minimum-gas-prices": "0basecro",
         "index-events": ["ethereum_tx.ethereumTxHash"],
-        "memiavl.enable": True,
-        "mempool.max-txs": MEMPOOL_SIZE,
-        "evm.block-executor": "block-stm",  # or "sequential"
-        "evm.block-stm-workers": 0,
-        "evm.block-stm-pre-estimate": True,
-        "json-rpc.enable-indexer": True,
+        "memiavl": {
+            "enable": True,
+            "cache-size": 0,
+        },
+        "mempool": {"max-txs": MEMPOOL_SIZE},
+        "evm": {
+            "block-executor": "block-stm",  # or "sequential"
+            "block-stm-workers": 0,
+            "block-stm-pre-estimate": True,
+        },
+        "json-rpc": {"enable-indexer": True},
     }
     # update persistent_peers and other configs in config.toml
-    config_patch = {
-        **default_config_patch,
-        **config_patch,
-        "p2p.persistent_peers": peers,
-    }
-    app_patch = {**default_app_patch, **app_patch}
+    config_patch = jsonmerge.merge(
+        default_config_patch,
+        jsonmerge.merge(
+            config_patch,
+            {"p2p": {"persistent_peers": peers}},
+        ),
+    )
+    app_patch = jsonmerge.merge(default_app_patch, app_patch)
     patch_toml(home / "config" / "config.toml", config_patch)
     patch_toml(home / "config" / "app.toml", app_patch)
 
diff --git a/testground/benchmark/benchmark/stateless.py b/testground/benchmark/benchmark/stateless.py
index 063a59e4ef..b836144475 100644
--- a/testground/benchmark/benchmark/stateless.py
+++ b/testground/benchmark/benchmark/stateless.py
@@ -91,14 +91,6 @@ def _gen(
     (outdir / VALIDATOR_GROUP).mkdir(parents=True, exist_ok=True)
     (outdir / FULLNODE_GROUP).mkdir(parents=True, exist_ok=True)
 
-    config_patch = (
-        json.loads(config_patch) if isinstance(config_patch, str) else config_patch
-    )
-    app_patch = json.loads(app_patch) if isinstance(app_patch, str) else app_patch
-    genesis_patch = (
-        json.loads(genesis_patch) if isinstance(genesis_patch, str) else genesis_patch
-    )
-
     peers = []
     for i in range(validators):
         print("init validator", i)
diff --git a/testground/benchmark/benchmark/utils.py b/testground/benchmark/benchmark/utils.py
index 172a956887..6cbab687a6 100644
--- a/testground/benchmark/benchmark/utils.py
+++ b/testground/benchmark/benchmark/utils.py
@@ -4,6 +4,7 @@
 from pathlib import Path
 
 import bech32
+import jsonmerge
 import requests
 import tomlkit
 import web3
@@ -15,26 +16,24 @@
 LOCAL_RPC = "http://localhost:26657"
 
 
-def patch_dict(doc, kwargs):
-    for k, v in kwargs.items():
-        keys = k.split(".")
-        assert len(keys) > 0
-        cur = doc
-        for section in keys[:-1]:
-            cur = cur[section]
-        cur[keys[-1]] = v
+def patch_toml_doc(doc, patch):
+    for k, v in patch.items():
+        if isinstance(v, dict):
+            patch_toml_doc(doc.setdefault(k, {}), v)
+        else:
+            doc[k] = v
 
 
-def patch_toml(path: Path, kwargs):
+def patch_toml(path: Path, patch):
     doc = tomlkit.parse(path.read_text())
-    patch_dict(doc, kwargs)
+    patch_toml_doc(doc, patch)
     path.write_text(tomlkit.dumps(doc))
     return doc
 
 
-def patch_json(path: Path, kwargs):
+def patch_json(path: Path, patch):
     doc = json.loads(path.read_text())
-    patch_dict(doc, kwargs)
+    doc = jsonmerge.merge(doc, patch)
     path.write_text(json.dumps(doc))
     return doc
 
diff --git a/testground/benchmark/poetry.lock b/testground/benchmark/poetry.lock
index d0e4207cb0..97de198f91 100644
--- a/testground/benchmark/poetry.lock
+++ b/testground/benchmark/poetry.lock
@@ -965,6 +965,20 @@ files = [
     {file = "iniconfig-2.0.0.tar.gz", hash = "sha256:2d91e135bf72d31a410b17c16da610a82cb55f6b0477d1a902134b24a455b8b3"},
 ]
 
+[[package]]
+name = "jsonmerge"
+version = "1.9.2"
+description = "Merge a series of JSON documents."
+optional = false
+python-versions = "*"
+files = [
+    {file = "jsonmerge-1.9.2-py3-none-any.whl", hash = "sha256:cab93ee7763fb51a4a09bbdab2eacf499ffb208ab94247ae86acea3e0e823b05"},
+    {file = "jsonmerge-1.9.2.tar.gz", hash = "sha256:c43757e0180b0e19b7ae4c130ad42a07cc580c31912f61f4823e8eaf2fa394a3"},
+]
+
+[package.dependencies]
+jsonschema = ">2.4.0"
+
 [[package]]
 name = "jsonschema"
 version = "4.22.0"
@@ -2188,4 +2202,4 @@ multidict = ">=4.0"
 [metadata]
 lock-version = "2.0"
 python-versions = "^3.11"
-content-hash = "f95059b65ce788a6cef6d06ec8d9dd9e65a819502003b2c3fa269647c0bc299d"
+content-hash = "0fb7ea7cb80f99d281286bd73bc04631c191c6b75b7375fa98cc9e590ff65074"
diff --git a/testground/benchmark/pyproject.toml b/testground/benchmark/pyproject.toml
index e626b7f291..0459065cf8 100644
--- a/testground/benchmark/pyproject.toml
+++ b/testground/benchmark/pyproject.toml
@@ -17,6 +17,7 @@ bech32 = "^1"
 requests = "^2.32"
 click = "^8.1.7"
 ujson = "^5.10.0"
+jsonmerge = "^1.9.2"
 
 [tool.poetry.dev-dependencies]
 pytest = "^8.2"