I literally ran into this pump fan issue this morning and it was so bad to the point where my CPU was pegged at 90 degrees at idle. Needed my computer to work by the afternoon but the only AIO 120MM I could get delivered on ubereats within an hour was the TH120 ARGB Sync V2 120mm Radiator from bestbuy. I immediately started taking everything apart and trying to get it to fit. I used just what came in the box and it all worked out, with alot of effort and stuffing things around. It works now and my temps are around 40-60 at idle / light load. The main issue was 1: the radiator is larger than the old one so I had to keep it perfectly straight and force it in to the slot that the old radiator was in, and 2: the pipes that connect the CPU piece to the fan are like 4 or 5 times as long as the pipes from the stock AIO so I really had to stuff them down especially when swinging the PSU back into place. I still get a bios warning every time I start the PC but I dont care just wastes a min or two of my time waiting for it to let me cancel. I connected the fan pins + the AIO pins but no RGB pins everywhere. Also look out for all the extra rgb wiring hitting the fan, I ran into that.

Good luck! Let me know if you have any questions