You've provided no details of installer bugs for me to look up. Bugs should be reported on bug trackers so developers can see it, otherwise they don't actually exist.
Your link provides provides mention of some things you didn't like relating to how you see user experience, but those were vague and often don't relate to the MATE experience at all.
Irregular graphic glitches in a couple Linux games.
these will not relate to the MATE desktop I bet at all, but relate to kernel being used, and kernel module (aka graphics driver) where specifics are required of what is running (both software stack & your hardware) is required; let alone not listing the games (so others can test for issues).
Volume would turn on or off by itself after waking up.
This is likely kernel related too; hardware details, plus kernel and other stack details are required. Kernels, kernel modules etc. are not issues that are dealt with by the Ubuntu-MATE, but by upstream Ubuntu project.
There was no bug report in your link, with very limited detail at all provided (in my opinion). Your returning to Linux Mint probably worked because it was likely using an older kernel I bet (ie. not 6.8) and is unrelated to the Ubuntu-MATE desktop at all.
Bug reports belong on bug trackers, which means launchpad for most of Ubuntu, though for Ubuntu-MATE you can also use Ubuntu MATE · GitHub
The ubuntu-desktop-installer
isn't Ubuntu MATE specific; as Ubuntu-MATE is only one of the 7 flavors using it (plus Ubuntu Desktop), so bugs relating to the installer need to reported so Ubuntu Developers are aware of the issue & can work in resolving issues; they don't use this site. Likewise the Ubuntu kernel developers use a different discourse site too.
Yes, many bugs can be reported here, and users of this site may decide to test it themselves, and then report the bug on bug-trackers for the original poster, but if you want issues resolved, it's best not to hope others do this for you; and report where it's got a chance of being fixed.