How much does storage speed affect your games?

I assume I'm not the only one who has played the same games on different type of storage: commonly HDDs and SSDs, but I also set up two RAID 0 filesystems (one on two HDDs, one on two SSDs), and I even installed Deep Rock Galactic on RAM.

However, more often than not loading times have been too similar across storage media.

I'm asking this mostly because I'm considering getting two SSDs dedicated to a RAID0 setup, as of now my RAID0/SSD filesystem is "only" 200GiB wide and it's sharing its drives with the OS and other things, but since I'm not short on space it may or may not be worth the price to set up a reasonably large FS with fast I/O.
I also suspect that my game loading times may be limited by the fact that I'm running most of them on Linux via proton, if everyone's experience contradicts mine then that's probably why; in fact, I'm pretty sure VKDX shader compilation adds some CPU-bound time.