I realize you have resolved the issue, but I thought I might contribute something.
A lot of people don't realize that the quality of the MicroSD card makes a big difference for running Raspberry Pi operating systems. High-speed is important, with a minimum of Class 10 (I know, newer/faster standards now exist) always being recommended. However, the endurance of the card (or the number of writes/re-writes it can handle) is just as important. There are "high endurance" or "industrial grade" MicroSD cards available that should do a better job than run-of-the-mill MicroSDs with Class 10 ratings and will have a longer life-span.
MicroSD cards were meant for storage, for photos and the like. Running an OS from a MicroSD card causes a lot of heat due to random reads/writes happening almost constantly. For the most part, they weren't designed for this purpose and the extra wear and tear can cause early failure.
Of course, running your OS from a real SSD would be best but that's tricky to get working right on a Pi4 (and probably not worth doing on anything older).