One thing I would stress is that these are really small files most likely backed by an SSD. The filesystem cache (in DRAM) can probably handle all of the files from a large repository without and performance hit. IOPS wouldn’t really matter
If you’re really worried about it then you can always warm the cache on startup by running vmtouch with some periodicity. It might be worth the Obsidian team to think about running a background process to do something like this but honestly I expect that this may be fixing a problem that won’t actually crop up