New mountain bike owner

Easiest solution will be a tailgate pad like others have said, though you risk denting your tailgate if you aren't careful and you can wear the paint off your bike where it sits. If you go this route and your bike has disk brakes just make sure the disk faces out.

I personally wouldn't recommend a system that requires removing the wheel. It's a pain at the end of a long ride, and if you have a nicer bike chances are it won't have a quick release so you'll need to pull out an allen wrench. If you've got disk brakes you'll also need to but a spacer between the pistons, or if you grab the brake when the wheel is off you may risk locking it up.

Your best bet is to get a hitch style carrier, which will free up your bed for other gear (which is great on bike trips) and allow you to have a shell on your truck too. 1up is definitely the best, though kuat, thule, yakima, rockymounts, saris, etc. all make good product. The difference will be the amount of bikes they can carry (some can add more on later if needed), tire size they can hold, weight they can hold, how much they weigh, how they prevent wobble in the hitch, and how they look.

You'll probably find that everywhere is sold out of hitch mount racks right now anyway, as COVID created a huge demand for outdoor related products, bikes especially. I'd recommend getting something used, and that'll give you a pretty good idea of what you do and don't like about it for if/when you upgrade later on. I got a screaming deal on an older thule rack with a 4 bike extension, that I'll probably use until something breaks and at that point I'd buy the 1up rack.

 

I've had fork mounts drilled into my bed but now I am gonna install some mob town bed bars and install some
Thule or Yakima fork mount trays on them. Keep my bed open for gear and stuff.

 

Tailgate pad — https://www.tacomaworld.com/threads/show-off-your-tailgate-pad-on-truck.576410/page-2#post-23884661