I've had similar issues with Amazon's equivalent too, where I tried to use EFS for a tiny website and I got something like 0.1 IOPS!

I do like the design of ZeroFS, and it irks me that competing solutions make local caching and buffering weirdly difficult. For example, Azure Premium SSD v2 disks no longer support local SSD caches! It's also annoyingly hard to combine the local cache disks you do get with remote disks using Windows Server, it insists on trying to detect the "role" of each disk instead of just letting admins specify that.

Using something like ZeroFS could be a nice trick for getting decent price/performance on public cloud platforms. My only concern is integrity and durability: what testing have you done to validate that it doesn't lose data even in corner-cases?