Shimano 12 speed road cassette / freehub compatibility

[NHAero]

Please un-confuse me..

Shimano lists two Ultegra 12 speed cassettes:
https://bike.shimano.com/products/co...-R8100-12.html
https://bike.shimano.com/products/co...-R8101-12.html

Both say they fit a HG L2 freehub. However, they also say "Shimano ULTEGRA R8150 drivetrains maximize efficiency thanks to larger cogs and retain compatibility with existing HYPERGLIDE FREEHUB bodies".

To confuse the matter further, i was looking at the ultralight ZTTO cassettes on Aliexpress. It looks to me that these fit the standard HG freehub.

If I am specifying a new set of wheels with DT240EXP hubs, what am I ordering for the freehub, and does it differ between the Ultegra and the ZTTO?

Thank you!