I have an older pool made years ago (MBR by defualt) which is around 80TB now with no performance issues. AS SSD shows it being aligned correctly.
I created a new pool on the latest build and by default it was created as GPT. This pool consists of SSDs but shows as not aligned properly (individual SSDs are aligned properly). I have very poor small write performance on the pooled drive, using the drives in standalone mode functions without issue.
All disks on the server are currently GPT (aside from the older Pool which was created as MBR)