Thanks for the reply @pavels. We use pixelArt: true, so the antialiasGL was already set to false, and my initial testing with changing batchSize does not seem to help.
With that said, I did spend the weekend putting throwing together a plugin that ports the compressed texture support from 3.60 to 3.24.1 (possibly other versions too, but I haven’t taken the time to test on any of them). Running 3.24.1 with compressed textures our game is back to 60fps, so now it’s just a matter of porting over some of the other functionality from 3.50 and 3.60 that we need. Would have been nice if the batchSize config change would have produced the same results it did for you. Let me know if there is anything else you can think might have help you with the issue =)
Cheers!
Fielding
P.S. If anybody else comes across this and has a need for compressed texture support in 3.24.1, this did the trick for me: GitHub - fielding/phaser-compresed-textures-plugin: Compressed texture plugin for phaser 3.24.1