You should set your sag correctly, period. Then use the damping to manage travel and behavior. Your compression damping could be why you’re not using more travel.
People don't know how to set up suspension (it appears you do) and there is so much conflicting info out there. Not saying I'm amazing at it either, but at least I understand the principles.
But to reiterate a few things:
1) Set rear sag on a 140-180mm bike at very close to 30% while SEATED. Let me say that again, while SEATED. On a coil shock the spring preload MUST be between 1-3 turns. If it's outside of that you need a different spring rate. Also worth noting that on a highly progressive bike, 30% at the shock shaft is not 30% at the rear wheel (and you need 30% at the wheel). My best guess is about 32-33% at the shock shaft is 30% at the rear wheel on any highly progressive bike. Setting sag correctly is the #1 most important first step before anything else is done.
2) Set front sag very close to 21% while STANDING in the attack position.
3) Try to base the rear shock spring to compliment the rear suspension design. I.e. linear coil shock combined with long travel progressive bike or small volume air shock with linear short travel XC bike. On a YT this means a coil shock, with a linear shock spring, not a Springdex. Not an air shock. But if you must use an air shock choose one with the largest air volume possible and no reducers.
4) Rebound is mostly about matching to the final spring rate. Start by riding slowly off a curb seated and try to get a single bounce (compress, extend, then settle). Set rebound as light as possible that gives you this. If you are in between, choose the less rebound (that means faster) setting.
5) Then set compression to use all travel softly on your most extreme events, should be 1-5 non-harsh bottom out events on your best ride days. But set LSC where the bike doesn't rock or bob much at all while pedaling. That is sort of your minimum LSC setting.
GL
PS. I'd also add that I don't love coil suspension. Especially in the fork as the fork doesn't have the advantage of a linkage to create progression. I think forks should be air. But coil shocks absolutely make the most sense on e-bikes. E-bikes, first are not as weight sensitive, Secondly, they cover a lot of miles/ kms and hit more stuff, day in & day out. Thirdly they are more likely to see different altitudes/ air pressure on a single ride. Fourth, coil is more reliable as it isn't tasked with holding high air pressure. Fifth, a coil spring rate is so hard to get set up right on a 30# bike as small variances in spring rates are very noticeable, but on a 50# e-bike the margin is much greater and just close enough is fine. On a bike just adding a hydration pack alters the ideal spring rate but, on an e-bike, you won't really notice.
So, my advice is to choose an e-bike with an appropriate leverage rate for a coil shock.
