The last thing I can suggest are the last two comments on the steam-devices repo: https://github.com/ValveSoftware/steam-devices/issues/64#issuecomment-3092449971

Try adding these to a file such as /etc/udev/rules.d/71-8bitdo-pro-2.rules

# 8bitdo pro 2 bluetooth hidraw
ACTION!="remove", KERNEL=="hidraw*", KERNELS=="*2DC8:6006*", MODE="0660", TAG+="uaccess"

and/or

ACTION!="remove", KERNEL=="hidraw*", KERNELS=="*2DC8:6012*", MODE="0660", TAG+="uaccess"

The reason I added ACTION!="remove" is due to a recent change with systemd.

ACLs for device nodes requested by "uaccess" udev tag are now always applied/updated by systemd-udevd through "uaccess" udev builtin, and systemd-logind no longer applies/updates ACLs but triggers "change" uevents to make systemd-udevd apply/update ACLs. Hence, the "uaccess" udev tag should be set not only on "add" action but also on "change" action, and it is highly recommended that the rule is applied all actions except for "remove" action.

Recommended example:

ACTION!="remove", SUBSYSTEM=="hidraw", TAG+="uaccess"

The following example does not work since v258:

ACTION=="add", SUBSYSTEM=="hidraw", TAG+="uaccess"