Depending on your usage of the watch, choosing the right case/protection is better when you have the watch at hand to feel the fit of it. I have had tried many cases and protection and the curved glass on the Apple Watch is a bitch. Constantly scratches non-stop when I go mountain biking.

It's not that, the casing that covers the screens but doesn't keep it sealed, will get condensation when exercising or swimming. Which doesn't allow you to interact with the watch. The other alternatives just protect the edges which leave the screen unprotected and prone to scratches. Then there are those plastic screen protectors but doesn't do well to cover all because the screen is curved. Hopefully someone makes a curved tempered glass screen protector for the Apple watch series.

Any extra glass is good, I have 3 other Apple watches with cracked screens already. Finally for me, enough is enough and I use a Garmin now for mountain biking

Instinct, flat surface and easy to install tempered glass protector. Its cheap and works well for mountain biking

The Garmin instinct? The battery lasts like 1 month LOL. I just leave it lying around in front of my desktop PC. Once in a while, I will remember to charge it.

Yes the GPS still works without the cellular function. I use my Apple watch to track my runs without the phone. The cellular is only if you want to receive calls during your run with your Airpods so that you can answer whilst on the go.
But if you don't expect to get any calls then don't need to get the cellular one. Also the cellular function helps you to stream music as well.

I have seen many people wear two watches at the same time! A mechanical watch on their main wrist and the AW on the secondary wrist for health tracking

Yeah, thats me as well. Ends up that my mechanical watches are all sitting at home literally collecting dust while I wear the Apple Watch more often

I would get the AW Pro as my current AW5 still suffers a lot when I mountain bike which makes me get a Garmin instead just for mountain biking.