I was thinking about Supermicro SLG3-2E4R SLG3-4E4T, SLG4-4E4T or generic equivalents, but that's not going to work in a SFF chassis.
Supermicro SLGx devices tend to require Supermicro board to operate. There are several threads here and other places, where the Supermicro Retimers/Redrivers do
not work on non-SMC motherboards as they require special functionality in the BIOS to operate.
I'd search before jumping on those.
A relatively cheap option is C-Payne adapters (if in EU) or Micro Sata Cables in USA - they have
m.2 slot redrivers (amazon link), PCIe slot ones and could ship to EU.