Android uses a 32-bit register to address sectors causing the infamous HDD 2 TByte limit with 512 byte sectors. Using the 512e trick one can access just over 16TByte with 4K Physical sectors emulating 8x 512 byte Logical Sectors hence 512e format.
https://www.futeko.com/newforum/index.php?topic=576.0
The unrelated cluster size is how big the OS writes the data single I/O in multiple logical sectors (up to 32K allowed but may increase slack with many small files on it).
But I may be mistaken as I see 18 TByte and 20 TByte drives advertised as 512e compatible. How they do that? Do they assume W10 64-bit OS using a 64-bit register for that? Will stick to max 16 TByte myself till I am convinced it can and will work flawless with Android 32-bit.
Some reported these drives working but others signaled disk errors found when inserted into a W10 PC next. Reducing the used partition size to 16TByte stopped those errors being seen.
Somebody tried finding the exact limiet: He claims it is 16.770.000MB (Win Explorer shows 15,9TB) which makes a lot of sense to me.