As long as you point towards the easiest way to join the fediverse first, while only “selling” federation as a feature for power users and people who are genuinely interested, then it doesn’t really matter how complicated the fediverse really is.
If your mom wants you to make her an email account, you don’t explain her how the entire mail system works, along with its history and while reciting a Richard Stallman manifesto about FOSS philosophy. You also don’t send her a link with 100 different email service providers, that all have their own small advantages or disadvantages, while also explaining her how to create her own mail service.
No, you just make her a Gmail account.
I think the official Mastodon app does a great job at simplifying on how to join mastodon. You have a big blue button that lets you join mastodon.social by default, while a smaller grey button is for users, that want another instance. I’m sure you could simplify this even more, but this is a great beginning.