Keep your present 3-pt. seat belts for street usage, they are much quicker & more convenient than the next seat belt I'll suggest.
I've installed 3" aircraft style seatbelts in both of my TJs for those trails where they are steep or offcamber enough to lock up the OE 3-pt. belts. Plus the wider 3" width & leather under the buckle makes them comfortable.
Like this one...
The benefits to this type of seat belt are many... it doesn't lock up on steep trails, it's wider so it's more comfortable, it has a big locking lever so it is easily locked/unlocked, and it is compatible with shoulder harnesses.
P.S. By the way, I have a barely used one like that one in the photo for sale, and it includes a new unused floor mounting eye-bolt mounting kit. I replaced it with a similar but slightly different style to work better with the new shoulder harnesses I just installed. PM me if interested.