You'll run into issues and not many people will be able to help. Debian, Fedora, and Ubuntu seem to be the popular distros rn for most people.

Agree with the broader conclusion that a first time linux user should probably avoid gentoo, arch, whatever, but its not because nobody will be able to help you, more just that the expected level of polish is a bit less.

It isn't considered a huge inconvenience to have to use the CLI or edit a config file by arch users, but for ubuntu especially they are more bent on building something that "just works" for most people (with the tradeoff being it's a commercially exploited product, and the innards of GNOME and the like tend to be more of a black box and less tweakable than say, a tiling WM)

But if you do want to dive in and learn how more of the internals work and how to configure things at a lower level, you will find a lot of help with issues, and very detailed documentation for a lot more things in Arch, vs Ubuntu. I find the ubuntu community online to be sort of a middle ground between the detailed technical help I've gotten from Arch communities, and the "here's some magic steps that worked for me, no idea why" type of thing that is prevalent on windows support communities.

Which isn't to say ubuntu people aren't helpful, but the critical mass of users isn't the only thing that matters, it also helps if the users are knowledgeable, and friendly (some arch people fail at this, though I've lucked out and really not had any bad experiences)