Can i use an adapter plate on a power collet chuck?

I feel kinda dumb asking, but…

I am planning on getting a new lathe which has an A2-6 spindle mount. My current machine has an A2-8 spindle mount. I have three collet chucks with A2-8 mounts that I’d rather not spend the $$ to replace right now. I see several companies selling A2-6 to A2-8 adapters… which mentally I completely understand but my existing collet nut that threads onto the end of the drawtube would be spaced away from the drawtube by the thickness of the backing plate which would be a problem, no?

Do backing plates not work for hydraulic collet chucks and are only for manual chucks? Or is the stroke of the drawtube generally sufficient to allow it to work as long as I make a thread adapter and/or a new collet nut? Or are backing plates just perhaps not compatible with collet chucks?

And lastly, is there any downside to using a backing plate other than the loss of Z-travel? Are they fine for accuracy? Do I need to spend the $2k+ for a top shelf unit from Kitagawa or is a cheaper unit from ATS/Royal/Dunham fine?

Wondering if it’s better to just buy a new collet chuck and sell the A2-8 ones to recoup some cost?