Assuming your Force MP500 240GB SSD is an M.2 NVMe drive, I wouldn't be too concerned if CrystalDiskMark shows 70C at times. NVMe drives are designed to run hot when working hard. The NAND memory chips can easily reach 70C and the controller chip 95C, at which point thermal throttling occurs. See the temperature graphs in this article.
https://www.maketecheasier.com/does-nvme-ssd-need-heatsink/
If your MP500 does not have a heatsink and is sitting in a "dead zone" on your motherboard underneath a large GPU with poor air circulation, then it's bound to get hot when reading/writing large amounts of data. I'd expect the SSD temperature to be significantly lower when the system is idling. We are of course assuming that Crystal is giving valid info. You could try touching the SSD (carefully) to confirm it's hot.
If you have a water-cooled CPU, there is unlikely to be much air flowing over the NVMe drive and the VRMs near the CPU. If your MP500 does not have a heatsink and is located in a "hot spot" near the CPU and under a GPU, then of course it will get hot.
Some people with water-cooled CPUs fit a small fan (60mm or 80mm) directed down at the VRMs next to the CPU waterblock. This fan could also provide air flow over an M.2 drive under the GPU.
An alternative is to buy and fit an M.2 heatsink, with or without its own miniature cooling fan. The Icy Box cooler shown below is overkill in most cases and probably won't fit in your case, but it shows what's possible.
Hard Disk Sentinel Pro displays the lowest and highest temperatures reached on all the drives in your system.