It’s a good thing. Understanding things you use is a good thing. Knowing things is a good thing.

Totally, but why should someone learn this thing over all the other things they can learn with their limited time in the day? Everyone has different priorities in life, and I'd expect this would rank very low for many people.

I think it’s absurd to consider this a UX friction

It sounds like you haven't had much exposure with respect to UX design (which is understandable, it's still a growing field). A key thing to consider is knowing your target user base. If Lemmy is meant exclusively for those that are fans of FOSS or are in the IT field, then it's probably doing ok. If Lemmy is meant to be something for anyone to use, then it's got a long way to go to meet the needs of the general population. What is considered simple or easy to understand for an engineer can be interpreted extremely differently by the target user. To get the right approach, options need testing and evaluation, and the design engineers need understanding and humility when they go back to the drawing board.

Just like finding a social media of choice today? It also doesn’t really matter, Lemmy instances aren’t Discord “servers”.

People gravitate towards the social media their friends and family are on. The corporate sites make it very simple. 1 corporation, 1 server, an email, a password, and you're good to go.

What’s wrong with it? I think it looks really cool actually. It’s clean, simple, and the colour scheme and it’s use is great. I’ve honestly no idea what “photon UI” is. After I signed up, I only browse Lemmy on my phone via Jerboa.

The base browser UI feels dated and maybe a step up from a wireframe design. I'm on Lemmy.world, so they offer a view different variants that look like a modern UI (like Photon and Alexandrite). It's nice because they're available on desktop and mobile browsers, but they don't always work, My friends don't use Lemmy, so I generally just send the base link from my Lemmy app of choice. They've learned to deal with it, but I doubt they'll be joining the Fediverse anytime soon.

That’s an issue of sorting and subscribing. Unsub to duplicate communities and change filter to something like “Scaled”.

This is UX friction. Why should someone need to set this up to get rid of duplication. If everyone is sharing the same article, then why shouldn't there be away to just see it once automatically? Why can't they see all comments from all federated instances in a single common link? Why do they have to do all this extra work just to get a simplified feed?

If so it’s all fairly intuitive. I’ve not heard anyone say otherwise until now either so I think this is just a personal issue.

Again, this is a UX design issue. What works from your perspective or sample size of users may not reflect the larger target audience.

I’ve not seen any NSFW comment on Lemmy period.

Your instance may not be federated with instances like Lemmynsfw. By default NSFW content is shown on Lemmy.world (at least if you're logged in). Yes, you are able to filter it out, but it's something you need to do yourself. I'm not saying having the content is bad, but it should be hidden by default from people's feeds.