With old CD players, the issue of how long it will be before it becomes irreparable may well be key.
To my old ears, no Naim CD player is better than my CDS2 until you get to a CD555. In addition, the gap between CDS2 and CDS3 is small and the gap between various CDXs was (iirc) even smaller, though the gap between CDS range and CDX range was not small.
Rega is different in that I think they promise to keep a diary mech for all their CD players. Naim CD players last a long time but this suggests Rega will last even longer.
For SQ, I would not swap my CDS2 for a Rega Saturn, but an Isis might well be a worthwhile jump.
However, when my CDS2 finally dies, I probably won’t buy any of these. Instead, I expect to buy a CD transport (probably from Audiolab) to plug into my NDX2 - or just get a Core and rip everything once.
In your situation, would keeping your CDX for now and then getting a pure transport when it dies be a worthwhile alternative?