diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 0b4b8bae1e384..b2fcb914e767b 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -72,7 +72,7 @@ jobs:
         run: |
           # Run tests on commits after the last merge commit and before the PR head commit
           # Use clang++, because it is a bit faster and uses less memory than g++
-          git rebase --exec "echo Running test-one-commit on \$( git log -1 ) && CC=clang CXX=clang++ cmake -B build -DWERROR=ON -DWITH_ZMQ=ON -DBUILD_GUI=ON -DBUILD_BENCH=ON -DBUILD_FUZZ_BINARY=ON -DWITH_BDB=ON -DWITH_USDT=ON -DCMAKE_CXX_FLAGS='-Wno-error=unused-member-function' && cmake --build build -j $(nproc) && ctest --output-on-failure --stop-on-failure --test-dir build -j $(nproc) && ./build/test/functional/test_runner.py -j $(( $(nproc) * 2 )) --combinedlogslen=99999999" ${{ env.TEST_BASE }}
+          git rebase --exec "echo Running test-one-commit on \$( git log -1 ) && CC=clang CXX=clang++ cmake -B build -DWERROR=ON -DWITH_ZMQ=ON -DBUILD_GUI=ON -DBUILD_BENCH=ON -DBUILD_FUZZ_BINARY=ON -DWITH_BDB=ON -DWITH_USDT=ON -DAPPEND_CXXFLAGS='-Wno-error=unused-member-function' && cmake --build build -j $(nproc) && ctest --output-on-failure --stop-on-failure --test-dir build -j $(nproc) && ./build/test/functional/test_runner.py -j $(( $(nproc) * 2 )) --combinedlogslen=99999999" ${{ env.TEST_BASE }}
 
   macos-native-arm64:
     name: ${{ matrix.job-name }}
diff --git a/ci/test/00_setup_env_arm.sh b/ci/test/00_setup_env_arm.sh
index 67e43aca0d1cc..da005f5a314d0 100755
--- a/ci/test/00_setup_env_arm.sh
+++ b/ci/test/00_setup_env_arm.sh
@@ -18,4 +18,4 @@ export RUN_FUNCTIONAL_TESTS=false
 export GOAL="install"
 # -Wno-psabi is to disable ABI warnings: "note: parameter passing for argument of type ... changed in GCC 7.1"
 # This could be removed once the ABI change warning does not show up by default
-export BITCOIN_CONFIG="-DREDUCE_EXPORTS=ON -DCMAKE_CXX_FLAGS='-Wno-psabi -Wno-error=maybe-uninitialized'"
+export BITCOIN_CONFIG="-DREDUCE_EXPORTS=ON -DAPPEND_CXXFLAGS='-Wno-psabi -Wno-error=maybe-uninitialized'"
diff --git a/ci/test/00_setup_env_i686_multiprocess.sh b/ci/test/00_setup_env_i686_multiprocess.sh
index e659486407934..cb19c44805176 100755
--- a/ci/test/00_setup_env_i686_multiprocess.sh
+++ b/ci/test/00_setup_env_i686_multiprocess.sh
@@ -18,7 +18,7 @@ export BITCOIN_CONFIG="\
  -DCMAKE_BUILD_TYPE=Debug \
  -DCMAKE_C_COMPILER='clang;-m32' \
  -DCMAKE_CXX_COMPILER='clang++;-m32' \
- -DCMAKE_CXX_FLAGS='-Wno-error=documentation' \
+ -DAPPEND_CXXFLAGS='-Wno-error=documentation' \
  -DAPPEND_CPPFLAGS='-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE' \
 "
 export BITCOIND=bitcoin-node  # Used in functional tests
diff --git a/ci/test/00_setup_env_native_asan.sh b/ci/test/00_setup_env_native_asan.sh
index d7ff7c2c1387f..28ce3d228e301 100755
--- a/ci/test/00_setup_env_native_asan.sh
+++ b/ci/test/00_setup_env_native_asan.sh
@@ -29,7 +29,6 @@ export BITCOIN_CONFIG="\
  -DCMAKE_C_COMPILER=clang-${APT_LLVM_V} \
  -DCMAKE_CXX_COMPILER=clang++-${APT_LLVM_V} \
  -DCMAKE_C_FLAGS='-ftrivial-auto-var-init=pattern' \
- -DCMAKE_CXX_FLAGS='-ftrivial-auto-var-init=pattern -Wno-error=deprecated-declarations' \
- -DAPPEND_CXXFLAGS='-std=c++23' \
+ -DAPPEND_CXXFLAGS='-std=c++23 -ftrivial-auto-var-init=pattern -Wno-error=deprecated-declarations' \
  -DAPPEND_CPPFLAGS='-DARENA_DEBUG -DDEBUG_LOCKORDER' \
 "
diff --git a/ci/test/00_setup_env_native_fuzz.sh b/ci/test/00_setup_env_native_fuzz.sh
index 597e2401a20eb..a627cfc69ec00 100755
--- a/ci/test/00_setup_env_native_fuzz.sh
+++ b/ci/test/00_setup_env_native_fuzz.sh
@@ -22,6 +22,6 @@ export BITCOIN_CONFIG="\
  -DCMAKE_C_COMPILER=clang-${APT_LLVM_V} \
  -DCMAKE_CXX_COMPILER=clang++-${APT_LLVM_V} \
  -DCMAKE_C_FLAGS='-ftrivial-auto-var-init=pattern' \
- -DCMAKE_CXX_FLAGS='-ftrivial-auto-var-init=pattern' \
+ -DAPPEND_CXXFLAGS='-ftrivial-auto-var-init=pattern' \
 "
 export LLVM_SYMBOLIZER_PATH="/usr/bin/llvm-symbolizer-${APT_LLVM_V}"
diff --git a/ci/test/00_setup_env_native_previous_releases.sh b/ci/test/00_setup_env_native_previous_releases.sh
index 19a33f14dd858..fc030f1e984eb 100755
--- a/ci/test/00_setup_env_native_previous_releases.sh
+++ b/ci/test/00_setup_env_native_previous_releases.sh
@@ -21,7 +21,7 @@ export BITCOIN_CONFIG="\
  -DCMAKE_BUILD_TYPE=Debug \
  -DCMAKE_C_FLAGS='-funsigned-char' \
  -DCMAKE_C_FLAGS_DEBUG='-g0 -O2' \
- -DCMAKE_CXX_FLAGS='-funsigned-char' \
+ -DAPPEND_CXXFLAGS='-funsigned-char' \
  -DCMAKE_CXX_FLAGS_DEBUG='-g0 -O2' \
  -DAPPEND_CPPFLAGS='-DBOOST_MULTI_INDEX_ENABLE_SAFE_MODE' \
 "
diff --git a/ci/test/00_setup_env_win64.sh b/ci/test/00_setup_env_win64.sh
index 985b2941bf214..9f6c51fa58178 100755
--- a/ci/test/00_setup_env_win64.sh
+++ b/ci/test/00_setup_env_win64.sh
@@ -21,4 +21,4 @@ export GOAL="deploy"
 # cross-compiling for Windows. https://sourceforge.net/p/mingw-w64/bugs/306/
 # https://github.com/mingw-w64/mingw-w64/commit/1690994f515910a31b9fb7c7bd3a52d4ba987abe
 export BITCOIN_CONFIG="-DREDUCE_EXPORTS=ON -DBUILD_GUI_TESTS=OFF \
--DCMAKE_CXX_FLAGS='-Wno-error=return-type -Wno-error=maybe-uninitialized -Wno-error=array-bounds'"
+-DAPPEND_CXXFLAGS='-Wno-error=return-type -Wno-error=maybe-uninitialized -Wno-error=array-bounds'"