Yeah, around this time last year I swapped out the 5400RPM hard drive in my Mac Mini because it was getting slow (especially with booting) with a 960 GB 2.5" SATA SSD that I was able to buy for just over $100. It really cut the startup time in half, and made opening applications a whole lot faster. This was when the Mac Mini still had MacOS 10.14 Mojave installed. So when I upgraded to Catalina, I had virtually no issues (at least once I upgraded my Tuxera NTFS software for use with external NTSF drives, and I found a 64-bit beta of the Boxer open-source DOS game emulator for the Mac OS.)