TLDR: I want to easily have a bunch of tabs somehow synchronized on both my desktop and mobile devices and in different groups. Safari and other iOS browsers haven't worked well for me.
This has actually been a hard problem I've been trying to solve for over 2 years now. Despite having used Firefox as my main browser the whole time, I had relied on Safari to sync tabs between my MBP and iOS devices since the UX for opening desktop tabs in the Firefox mobile app is really clunky: you have to do lots of taps and to get a list of tabs and you can only open one at a time, to open just one tab you have to do the whole dance all over again (this was from last time I tried it months ago, is it any different now?).
The problem with Safari is that lose a whole bunch of tabs can suddenly disappear open on all devices, replacing the pages with blank tabs, you can image how pissed off I was at that. I tried a bunch of iOS browsers, but none of them came close to having a UI as good as Safari in my opinion, and honestly iOS Safari feels much nicer than Firefox. Later I found Orion, but if I have many tabs open, the browser lags really hard on my M1 iPad Pro and iPhone 14 Pro Max, when all of them except for the current tab are unloaded. I don't get why mobile browsers are generally unpolished compared to desktop ones.
I was opposed to read it later apps like Pocket and Omnivore, because I can't open a bunch of pages quickly and switch between them, like I can with browser tabs, but I think I have to suck it up. I could use the Omnivore iOS app and have a tab open on Firefox desktop, to save page and open them in the browser by default, and it has labels which I can filter pages by, since I like to have pages or tabs in groups like Safari Tab groups.
Having long lists of pages wouldn't lag, or suddenly disappear, and I can mark the pages as read when I'm done with them. I wonder if anyone has any thoughts on this or have other ideas that might work better.