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