Hello Ulrich :-)
Makes it kind of hard to install kresd. :-)
Ah, I'm sorry. Off the top of my head I'm not sure what will be
best, but I'd recommend you to switch to our new packaging
infrastructure that contains both 5.x and 6.x, and it does armhf
and arm64 (covering all except the oldest raspberries, I think).
https://pkg.labs.nic.cz/doc/?project=knot-resolver
--Vladimir