Oh ok. That's due to a bug that was fixed in v0.9.8. It will be fixed when i release the next free version. If you want to see what the performance will be like, you can try out the demo, It's based on v0.9.8 and includes that fix
Thanks. Re: textures - I can't remove textures in the arenas - they're pretty much integrated, and it would create a lot of complexity when it comes to modded arenas and such. But I strongly doubt textures are what cause framerate drops. Following 0.9.8 and the performance fix I've had people with very old devices getting a pretty big performance boost, in some cases up to 100% or even more.
One thing to try: select Low or Medium resolution in Options, and go for FSR ultra quality or quality.