Systems like Ubuntu, Suse, etc. should "just work" with secure boot. This has been the case for over 10 years (Ubuntu starting with 12.04, in a quick check). I just run a custom hacked-up version of Void Linux because I'm cool like that, but no one new to Linux is doing that – they start out with Ubuntu or such, just as I started out with Mandrake back in the day.

Also I actually got my laptop with Ubuntu pre-installed, a concept that barely existed in 2000.