If you want to say that development processess and testing could be improved, I'm with you. If you are actually saying you want to help testing, especially with regard to mobile behaviour, I would very much like that.
I asked to be part of testing a long long time ago and was not given any special access. I have no reason to believe anything will change if I ask to help again, and I'm not going to reach out to Stef and be ignored. If he wants me he's going to have to ask me himself and I would be large amounts of money that he won't.
But on the other hand if I have a chance to actually be heard and improve the software I'm not going to turn it down
For the game, as always, the question if to revert a change or work on a fast fix is not easy. I think you are right that in this case the time for a quick fix is too long. But let's be sure, that is about the chat problems, not your button problem.
This is not a hard problem, it's not a question. You don't release software with bugs because you test it. If bugs get by testing then you obviously want to improve your testing in the future to catch those bugs, but you don't let bugged software stay out there for users for any length of time at all. You revert the changes so that users don't have to use software with bugs until you fix the bugs.
Reverting can be done in a matter of minutes and you go back to a known-good state that has gone through all of your own testing plus users having time to find things that may have slipped through. Any bug fix with proper testing will take longer than that, even if it's just a one-line fix. Considering any other course of action for any piece of software ever is simply bad practice. I don't need to know anything at all about your software to tell you this. This is just how software development works. You don't let releases sit out there with bugs in them that you can fix by reverting to a previous version. Ever. The end.
While of course you may have the opinion that the new placement is much worse, to me it seems just that, your opinion.
I don't know how to tell you this other than that you are absolutely wrong. Read this thread, there have been zero positive comments about the button placement and color and several negative ones from at least 4 different users if you look back the last couple of releases when it started to change.
The fact that you just want to wave your hand at this and say it's OK without soliciting any feedback from your users is a systemic problem that Shuffleit has. Please stop. This change is extremely bad and you're just putting on your blinders and saying that it's good.
You don't get to decide if your UI is good, your users do. That's how UI works. Ask your users and find out what's working and what isn't. Your software has vastly suffered since before the first release because of this.
It is not hard to solicit feedback from your users. Make a poll on this website. Go do a Discord server and make a poll. You can get a general idea of what the community thinks so that you don't have to just guess and make awful design and implementation decisions and then stick with them and make your software worse.