I would echo a lot of what Matt wrote above.
If you're starting mountain biking don't go out and spend many thousands on a top line carbon full frame bike. My 1st bike had no suspension and I didn't add a front to it until I started getting pain in my arms due to the speed I was going down bumpy trails. After that mind you it's a downhill battle (pun intended) to keep your wallet closed and mine is pretty worn.
I've had 2 bikes stolen, both covered under my homeowners policy. I don't know anyone with separate insurance but none of us have e-bikes, and if I did I'd be looking at an e-mountain bike and still not get insurance.