How much sound quality matters versus convenience varies, so pick what suits you.
I ripped my CDs as a back-up and/or to cover obscure choices and/ or possible hiccups to internet/ WiFi, but almost all my digital listening is Hi-Res on Qobuz. If your internet & Wifi are reliable, and if you are happy to commit to paying for a streaming service forever to hear music that you already own today, then I don’t see the downside to getting rid of CDs and CD player.
For serious listening (e.g. not while doing other things around the house, chatting to several friends etc.), I still find that my (comparable) LP12 is more enjoyable & involving than any digital options, so mine is staying. If you don’t find that once you have tried a good streamer, or eyesight means that using the LP12 is increasingly annoying, then selling it makes sense. Mind you, you don’t have to decide that at the same time.
I agree with others that the rest of your system can certainly justify getting the NDX2 and the XPS, which is what I use - the XPS makes a noticeable difference. However, the NDX2 is pretty good without the XPS too.
Overall, I’d suggest getting a Qobus (or perhaps Tidal) subscription and an NDX2 first. Try streaming, and see which of your treasured LPs are simply unavailable on streaming services. If all the music you like is available and it sounds just as good to you as the LP12, your choices will look easier.
After you have an NDX2 and have got used to it, and have sold/ decided to keep the LP12, you can go to a shop, hear the NDX2 with XPS and decide whether that too is worth the money to you.
Finally, if total cost is important, you don’t have to spend fortunes on streaming. The ND5XS2 has no screen or buttons, sounds a bit less good than the NDX2 if assessed carefully, and lacks the upgrade options of an NDX2. However, it is still very good and I just bought one (for a different hi-fi system) for £2K on a well-known action site. I’d personally be surprised if an ND5XS2 with a Hi-Resolution/ “lossless” service did not sound at least as good as your CD player.
Selling CDs may be hard and selling vinyl bothersome. However, if the ND5XS2 is actually all the hi-fi source that you actually want, then the switch from LP12 and CD5XS should show a fat profit.
Good luck!