I've just contacted Gigabyte Support and the answer has been:
"Dear customer,
Thank you for emailing GIGABYTE.
We are delighted with your interest in our products.
X570 AORUS XTREME is EOL and sold out.
Check X570 AORUS Master.
Regards
GIGABYTE Team"
So they recommend me the X570 Aorus...
in another forum, a Gigabyte rep said: "There will be some new X570 boards in the near future, these are not for 5000 series though. It's to add official thunderbolt support for some new models now AMD chipsets can be ratified. No dates for these yet but all the current X570 will support the new...