Remix is _really_ great if you want a traditional web application. In the tutorial they (used to?) do a bait and switch on you where at one point you realize no client side JavaScript has been running the entire time because the tutorial hadn't even talked you through how to bundle in the client side js! The idea is pretty much, use the platform.
Of course, I'm building a web app on top of it, so I want a lot of features that "the platform" doesn't necessarily support very well without client-side js to facilitate everything. And I did make an honest go of it. To me, the biggest pain point is still forms and form validation, which is notoriously painful in React land. I'm ultimately using react-hook-form and running the same schema validator client-side and server-side, which means I'm not really "using the platform" in that respect. I'd love to see an official react-hook-form type solution added to Remix.
Still, the framework has some really great, sticky conventions and it feels like they thought of almost everything. For example, the "action" and "loader" convention is awesome, nested layouts are the bomb, they encourage filenames like .server.ts to differentiate between things that can't be run client-side, heavily encourage the use of a bunch of goodies from react-router (which most people probably don't know exist) because Remix's routing is built on top of react-router... And so on.
Having used both Next.js and Remix a few times, it's difficult for me to recommend one definitively over the other; if you aren't experienced with them either one will be a learning curve. In general, I think Remix is the better framework but some shortcomings in the documentation (e.g. I found out about some new routing conventions because the old ones weren't working for me and it was confusing because the tutorial and docs seemed to use the old ones) and the relative dearth of resources online can lead to frustration. This should pretty much be a non-issue if you start a new project with one of the "stacks" that someone has developed, the blessed ones of which give you a base project that already has database, authentication, tailwinds etc configured with example routes and components.
Next is already taking some of the good ideas from Remix (nested layouts still in beta I think), and has a pretty extensive and mature ecosystem with lots of answers on SO and blogs at this point. For example, if you want free social auth you're pretty much just going to install next-auth. Still don't know exactly what I'd do in Remix for that.