Installing a water block is not difficult especially if your getting the block from a reputable manufacturer and their directions are written in whatever langue you understand. I've had to use Google translate to translate Chinese to English when I got a really cheap Byski card once. Pretty much make sure everything tightened down and your fittings are secure and your good to go.
Turning the massive RTX 4090 GPU into a 1-slot compact card is easy with the Alphacool reference design enterprise-level waterblock with backplate. The compact design also reduces the card length by almost 50%, but it only works with INNO3D models.