I don’t use PLA filament but I recently had a battle with 60% overhangs using ASA and I can confirm the Slow Down for Overhangs features works in Orca Slicer but perhaps Bambu has issues. I only use Orca Slicer and find it much better. Bambu has an excellent Wiki on the feature here.
What worked for me was to slow the overhangs way down to 10mm/s and use 100% cooling on overhangs. Using a 0.6mm nozzle helps immensely too and would be a great fit for that particular model.
