Here, this has helped fix almost all issues with stuttering (fps dips) and audio dropping. It glitches here and there but def makes it playable
Audio fix
\SteamLibrary\steamapps\common\Helldivers 2\data\settings.ini
change
"memory_size = 78643200"
FPS Fix
Press Windows Key + R to open the Run dialog.
Paste %APPDATA%/Arrowhead/Helldivers2 into the Run dialog and click OK.
In this folder, you will see a file called user_settings.config.
Open it using notepad or any other text editor you wish, and make the following adjustments before saving the file:
particles_cast_shadows = false
particles_local_lighting = false
particles_tesselation = false
particles_receive_shadows = true
lens_quality_enabled = false