Generally speaking on-board amp compression is terrible, so a compressor pedal will do a better job for you, but if you like the results that you are getting, no need to make a change.
Never hurts to have a boost, clean and/or dirty. Lots of options to try in that arena.
I wouldn't be so aversive to stacking your dirt pedals, but to each their own, if it doesn't work for you, nothing wrong with that!
Finally, there are endless flavours of dirt pedals to try, you can never have enough of those. Again, if you like the ones you have, no need to change, but I feel pretty confident in saying you'd like others even more.