Very much this.

I've attempted (largely unsuccessfully) to try to use Pocket (also a Mozilla product) to address this. The problem with Pocket is that it gets worse the more you use it. From four years ago:

https://old.reddit.com/r/dredmorbius/comments/5x2sfx/pocket_...

A couple of those issues have been addressed. There's now "find in page" on the Android app, and editing tags is very slightly improved. But overall, Pocket remains a roach motel: articles check in but they never check out.

What I really want is a persistant, local, tagged, searchable, entirely-offline-usable archive of content. There seems to be little interest (or supreme obstacles) in providing this. (I've looked at Zotero, Calibre, and Mendalay, none really suit my workflow.)

I've utterly given up any hope of browser vendors delivering this.

Pinboard.in seems okay though

That or Wallabag, both of which I've read quite a bit about but not tried.

Self-hosted Wallabag is ... on my to-do list.