I have a Lenovo L14 (AMD) with the same wifi card and on my home router I have the same issue, I get download speeds of 1-2 Mbit/s. In other places it works fine.
I can fix the issue by adding the following lines to my /etc/modprobe.d/iwlwifi.conf:
options iwlwifi disable_11ax=Y
options iwlwifi 11n_disable=1
but wifi speed in other places is slower then.
dmesg shows the following:
[ 1.896694] iwlwifi 0000:03:00.0: Direct firmware load for iwlwifi-cc-a0-56.ucode failed with error -2
and doing some digging reveals that manjaro provides a couple of similarly named files in /lib/firmware, iwlwifi/cc-a0-**.ucode but not the one requested.
Not sure if the file is missing or just has the wrong name.