Reverting Firefox Design Updates

Hi, I'm autistic and I find the new design updates really, really disturbing and I need to change it back to the old design. I read on the help article for reverting to older versions that it'd be better to ask if there's a workaround instead of downgrading because of the security issues, so yeah '''does anyone know how to revert to the previous Firefox design and maintain the current version of the browser?''' By the new design, I mean the roundness of everything and the teardrop shapes for whatever's left. I'm still gonna revert back for now but hopefully there's a fix I can use.