Practice in a VM. Go from the base install to setting up all the apps to customizing the look of everything (commonly called “ricing”). That should give you a sense of what to expect.
When you think you’re ready, maybe give a few Live ISO’s a demo to see if there’s any immediate glaring issues when it’s running on bare metal. If not, then proceed to install when you’ve picked the one you like the most!
I know people have recommended Bazzite already, and I would too, but be sure to give PikaOS a look as well.
It’s a gaming distro, but it’s not immutable/atomic, though it uses a similar build process. Definitely one to consider if gaming is your goal.