Debian 11 Bullseye installs the udisks2 package, which allow storage devices to be mounted in user sapace.
We prefer to have the fmask=0133 mount option when mounting external exFAT storage device (e.g. SD card from the action camera); having the exec bit enabled on images and videos is quite annoying.
Create the file /etc/udisks2/mount_options.conf with:
[defaults] exfat_defaults=uid=$UID,gid=$GID,fmask=0133
Restart the daemon with
systemctl restart udisks2.service
then check that you can mount a device using a regular unprivileged user:
udisksctl mount -b /dev/sdb1
Using mount verify that the mounting options are the ones expected:
rw,nosuid,nodev,relatime,uid=1000,gid=1000,fmask=0133,dmask=0022,
iocharset=utf8,errors=remount-ro,uhelper=udisks2