diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index cc0689f9c6..2ac170d047 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -43,6 +43,8 @@ jobs:
               -DBUILD_LTO_LIBS=ON
               -DD_COMPILER_FLAGS=-gcc=/usr/bin/c++
               -DCMAKE_EXE_LINKER_FLAGS=-L/usr/local/lib
+            # ^^ /usr/local/lib/libzstd.dylib detected/used during LLVM build => `-lzstd` part of `llvm-config --system-libs`
+            #
             # https://github.com/ldc-developers/ldc/issues/4462:
             # When using LTO, we need to explicitly export ~all symbols for plugin support via `ld64 -exported_symbol '__*'`.
             # Additionally `-w` to suppress resulting linker warnings.
@@ -60,12 +62,14 @@ jobs:
               -DBUILD_LTO_LIBS=ON
               -DD_COMPILER_FLAGS=-gcc=/usr/bin/c++
               -DCMAKE_EXE_LINKER_FLAGS=-L/opt/homebrew/opt/zstd/lib
+            # ^^ seems like an LLVM bug - no libzstd detected/used during LLVM build, yet part of --system-libs apparently
             extra_cmake_flags: >-
               -DBUILD_LTO_LIBS=ON
               -DD_COMPILER_FLAGS="-gcc=/usr/bin/c++ -O -flto=full -defaultlib=phobos2-ldc-lto,druntime-ldc-lto -L-exported_symbol '-L__*' -L-w"
               -DCMAKE_EXE_LINKER_FLAGS=-L/opt/homebrew/opt/zstd/lib
+            # FIXME: 'LLVM ERROR: Unsupported stack probing method' when extending LTO to C++ parts and trying to link ldc2
             # -DEXTRA_CXXFLAGS=-flto=full
-            with_pgo: true
+            with_pgo: false # FIXME: ldc2-unittest hangs at runtime (at least sometimes?) with LTO+PGO
 
           - job_name: Windows x64
             os: windows-2022