Ah sorry, I missed that you’re based in Europe!
Unfortunately HaLowLink 1 is not available in Europe yet, see HalowLink-1 Firmware for Germany.
This is because MM6108-based modules require different SAW filters depending on the region they are certified for, so the MM6108 module that is in HaLowLink 1 wouldn’t work well on EU frequencies. With the new MM8108 chip this won’t be a problem anymore, see my recent post here for more information: HaLow Support for EU Region - #2 by flex84
It would be good to confirm that you’re indeed using a EU module (made for CE certification) on both ends, as using EU channels on a US module (made for FCC certification) won’t work well.
Note that most of stuff sold on Alieexpress that is marketed as Wi-Fi HaLow is in fact not really Wi-Fi HaLow and can’t be certified / won’t interoperate. Most of these devices also won’t meet CE certification requirements, so they’re not a great reference point.