This sounds like my experience of the Apple Watch Series 3—absolute garbage for exercise. I think the problem is the GPS hasn’t locked on when you start the run but there’s no way to know this in the UI. The only solution I’ve found is to “start” early, immediately pause, then wait a bit for GPS to locate you before unpausing.
Most sports watches solve this problem by explicitly telling you your GPS status when you are getting ready to track your exercise.
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's entire line-up is pretty great. They focus on things that matter: honest GPS measurements and battery life being at the top of the list. I really like some of the new Tactix 7 features, like the ability to remember the route but forget the geo coordinates.
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.
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.
Most sports watches solve this problem by explicitly telling you your GPS status when you are getting ready to track your exercise.