A FBL unit can usually compensate for CCPM interactions just by the way it works, but it's not optimal for it to have to do that. Some units have settings that allow you dial those out. The Mikado Vbar, for instance, has settings in the setup menu to dial out interactions at the extremes of travel (i.e. at full or minimum collective, you can dial out a swashplate tilt).
Is fbl less prone to ccpm servo interaction or poor set in flight compared to a flybar set up.
Some units, like the BeastX will actually work ok with things really goofed up in the mechanics - I once had unequal travel setup on the swash on my 700E by accident (balls on inner holes on the AIL/ELE bellcranks, but elevator A arm was on outer holes) and it actually flew fine. No idea how it was dealing with that, but I only discovered my error on the bench later.
But obviously you don't want things messed up to that degree
So I'd say the constraints are the same - you want it setup right else odd things are likely to happen in the air. So FBL won't relieve you of that
And what about use of sub trims and or travel adjust on radio with fbl. I dont know much about fbl. Thinking about converting over to fbl.
The main difference there is the CCPM mixing is typically done in the FBL unit itself rather than in the radio software as is the case with flybar. So normally subtrim settings and travel adjustments are handled on the FBL unit rather than in the transmitter. The transmitter typically is setup with an "H-1" heli model (one servo on each of collective, ail and elevator, like in the old days where we used mechanical mixing rather than CCPM) and the FBL does the mixing.
So it's a bit of a departure from what you're familiar with. I would suggest a unit with a good setup or software, like the BeastX or Vbar. The Vbar has far and away the best software of any of the other units and is probably the easiest to setup. It requires a computer, but IMO it would be the gentlest introduction to FBL. Next would be the BeastX, though its setup is a little more arcane at first. But once you get used to it, it's a cinch.
I won't go into the ones that I'd recommend against here. PM me if you're interested in that.