I think current Element versions accept either a recovery key or recovery passphrase in the same input field, so there's no getting it wrong. Since you seem focused on UI, it's worth noting that Element X (their beta mobile app) has a greatly simplified interface; their team clearly has been working to make it easier.

Also, other clients exist.

For whatever it's worth, I've been using Matrix for about five years, including some of its roughest times. I seldom see errors these days, but I can understand how folks who were frustrated with earlier iterations would still be soured to it. Such is the nature of an ambitious work in progress, I suppose.

I use it because there is nothing else with the combination of features that are most important to me, and because (despite my gripes) I can see slow and steady improvement. I think it's moving in the right direction overall. I could picture introducing family members to it once Matrix 2.0 is released and the implementations shake out any early problems.