While I believe the kinematics could be re-used, changing the controller out seems like it would be a challenge without designing a new print head. Their print head has a controller on it with firmware that you would need to understand how to control or you would need to change out in place of direct wiring back to the main control board. I don’t think you could just take something like Marlin off the shelf and interface it to the print head without a bunch of additional development work.
I got my Delta+ from the kickstarter and personally felt they kind of abandoned improvements to the printer after they got them all shipped out. Flux Studio really wasn’t all that great and they only put out a few updates until they needed it for their new laser cutter. The print surfaces they sold never held up unless you ripped off the thin build layer they put on and put a better third party one on the magnet, then I was able to use the same one forever. My prints off it were never really that great, certainly not as good as off a Prusa MK2 which was sold at relatively the same price point. I could never print anything that needed to rotate or move after printing in place because the tolerances just were not there. I ended up only using it for “trinkets”. My Delta+ tears the crap out of filament when its extruding to the point where sometimes I think it jams because there is too much friction from all the damage the extruder gear did to the filament. There should be a user accessible way to adjust filament tension but there isn’t. A printer at the price point of the Flux Delta should work better than this out of the box. I’ve done more successful prints on my Prusa Mini in 4 months than I ever got off my Delta+ in all the years I have had it.
As a result of what I felt was a lack of follow up on fixing design flaws mentioned above, I never seriously even considered their laser cutters when they went in that direction.
They had a lot of cool novel concepts but the market has really changed. You can buy an Ender 3 V2 for the cost of two print heads and get a bigger print volume, silent drivers, a glass plate and more reliability.
I am not sure the level of effort to update a Flux Delta with a modern board and fix the extrusion path is worth it for the results it produces today. Personally, I would just buy a new printer if I needed any replacement parts that costs more than a few bucks.