Thunder, on android. I've tried voyager, and the UI makes me want to vomit. Everyone seems to love it, and it probably works great, but... no, I can't do it. I tried a couple more but I'm not sure if they are cross-platform. Regardless, thunder 100%.
I came from reddit using RedReader for a decade+, and since RR is supposed to have Lemmy support eventually but still doesn't, I needed a stand-in that was similar. Thunder was the first one I tried and it's very close, so I tried a couple others but ended up keeping thunder. Until RR implements lemmy support, I'm happy enough. Using it for a couple years now.
Only real complaint is that I can't reply/compose 'direct messages'. It'll do comments and posts fine, and you can read messages from users, but it won't let you answer. Gotta open the browser and do it that way. It used to be pretty buggy, crashing and hanging, but that was a while ago. Pleasant experience for a bit now.
PWA for me just isn't the same, significant downgrade. I browse lemmy basically exclusively on mobile, I want the full experience that an application provides.