Hi,
It's a recurring question in this same forum, asked again no later than yesterday, take a look at the threads of these last days / months, in any case an excellent document, IMHO better usable than the classic "official documentation" can be find here:
https://core.vmware.com/resource/esxi-system-storage-changes#section1
Personally, for ESXi installation (bare metal or nested, I make no distinction) the "boot disk" on which I install ESXi 7.0U3x / 8.0x has a minimum capacity of 128 Gigabyte or (often) more and no USB drive whatsoever, approach that I see shared by others writing in this forum.
Regards,
Ferdinando
