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This won't be an exact answer. I think with the way it's described, there could be many reasons why the issue manifests. However, the good news is that the live ISO works, therefore the problem is NOT a bug in the Linux kernel or Ubuntu OS.

I think that if you did a fresh install of Ubuntu, your hardware would probably work again. Unfortunately you would also lose your installed packages and your user configuration. If that is okay, stop reading here and do a fresh install, because IIRC it takes ~20 min to install Ubuntu and it is very unlikely that you can do troubleshoot this in less time.

To avoid a fresh install, you would have to systematically compare the live env and your own system. Luckily in Linux everything is a file, so you can use tools like `diff` for this.

There are going to be many differences between the live ISO and your system. I would say the first step is to figure out whether the issue is system level or OS level. Simply create a new user account, reboot (in case your normal account somehow modifies the system on login) and login as the new one. If the issue persists (I'm guessing it will), you can consider it system level.

* User level configs are, in the vast majority of cases, under `~`. If the problem is in your home dir, possibly somewhere like `~/.config`. List all dirs with `ls -a ~` and start copying them over one by one into the new user until the new user also breaks. You can then expeirment with subdirs until you find the exact file and line that causes it.
* System level configs are mostly in `/etc`. There are also things like the configuration of the kernel or bootloader, which are elsewhere, but the good news is that usually these in turn are also controlled from `/etc`. For example, `/boot/grub/grub.cfg` contains Grub settings and the initial image but they are generated from `/etc/default/grub` with `update-grub`. So you can diff the live ISO's `/etc` vs your existing system's `/etc` and see if you find anything suspicious. You can then try to copy over the live ISO's version of the file to see if that fixes it. Be careful though, some files in `/etc` might break your system if you revert them to the live ISO's version (for example, `/etc/fstab` on the live ISO will be wrong for your actual OS), so read up on each file before messing with it.

Also, if the problem is user-level that means your existing home dir is "clean" (which is likely - it's hard to disable devices from `~`). That means that if you do decide to do a fresh install, you can simply copy over your old home dir to the new install, and restore your settings. Your packages will still be a lost, but you can export a list of them and then batch-install it in the new OS (I would suggest posting a separate question for how to do this).