I have similar thoughts as OP (though I now use a Series 7 and have few to no issues with GPS now) - the Garmin Fenix 5 or Coros Pace 2 are pretty great. Ive done trail ultra's, road halfs, mixed bike races, city to city tours and everything in between with both. Coros doesnt integrate with as many things as I would like.

Garmin user for ages. Forerunner 9 series is my jam but you might want to find what works in your price point along with the need-to-have/want-to-have feature matrix of your choosing. Garmin's UX is stuck in the Symbian era of OS design. So I appreciate the competition that Apple brings to this segment.

Sport gear reviewer DC Rainmaker has a full write up on the good/bad/ugly of the Apple watch for athletes[0]. He also has plenty of other reviews on other brands of sports watches if you want to see what is out there for you.

[0] https://www.dcrainmaker.com/2022/09/apple-watch-ultra-in-dep...

If you already have an Apple Watch, I recommend trying WorkOutDoors before looking for another device. It’s a huge step up from the default workout app that I’m still using my Series 3 for everything up to marathons.

I’ve only used the Garmin and it’s pretty good. The 735XT (old model) is still serving me well, though the battery is dying. I did get a 935 but something was wrong causing it to keep restarting. Apart from that it was fine, though.

Garmin for sure. I use a Fenix series but they have the Forerunner too.

I hear Suunto watches are good too. Basically any company that has been in the GPS space for a long time. Garmin has been doing GPS since long before Apple contemplated making phones.