The simplest and easiest way to do this is to copy the hidden files to new installations. Not all hidden files, only the pertinent ones or you'll cause problems in your new system. There's 2 hidden files you'll want to copy:
.mozilla (firefox)
.thunderbird
These are found in your home folder. Hidden files have a full stop as the first character in their name. Copying these in to a new system means that all your email accounts are already set up, all your old emails are still there, all your internet bookmarks are retained as well as saved logins and passwords.
The .mozilla file has a trick to catch you out though, it doesn't properly overwrite any existing .mozilla file so you need to delete the newer existing file before copying your old one in.
You can do this too, very handy for people that have poor or expensive internet services. There used to be a wonderful Canadian service called OS Disc but they shut down in 2019. I had a quick look around and found this one:
https://www.thelinuxshop.co.uk/
If you're having trouble getting hardware to run correctly then I recommend you try Fedora Linux. Most distributions only come with a "current" set of hardware drivers. This means no drivers and poor support for both older hardware and for the latest and greatest. Fedora is the only one I've come across that operates everything correctly straight out of the box.
That said, I've been using Ubuntu again for the last 6 months but I'm fed up with it again now and will shortly be going back to Fedora.
https://spins.fedoraproject.org/en/cinnamon/