Is the underlying forum software hard-coded to Google-Chrome? My "daily driver" browser is Pale Moon https://www.palemoon.org/ which was forked from Firefox way back when Firefox was still a decent browser (don't get me started).
1) I was not able to create my account in Pale Moon. I had to use Google-Chrome.
2) I am not able to upload images in Pale Moon. I have to use Google-Chrome.
I use Google-Chrome only when necessary, and I fumble around a lot because of my unfamiliarity with it.