I use both, debian on servers and old machines, arch on my desktop. Arch being rough is way overblown in my experience, the install script makes it straightforward to setup and it’s been pretty much painless since I switched to it two years ago, I had experience with debian before that. Both arch and debian have fantastic documentation available.

Debian and derivatives, in my experience, are really well supported so that’s a plus. Age of packages has never really bothered me and cases where I want bleeding edge there’s options for that.

Both are solid options and I don’t think you’ll be upset either way, if you can I’d try both.