Moving MySQL tmpdir to volume mounted on droplet

I want to move my tmpdir to a mounted volume on my ubuntu droplet.

I created the 50G volume, mounted it with these steps, per the config instructions

# Create a mount point for your volume:
$ mkdir -p /mnt/volume_nyc3_01

# Mount your volume at the newly-created mount point:
$ mount -o discard,defaults,noatime /dev/disk/by-id/scsi-0DO_Volume_volume-nyc3-01 /mnt/volume_nyc3_01

# Change fstab so the volume will be mounted after a reboot
$ echo '/dev/disk/by-id/scsi-0DO_Volume_volume-nyc3-01 /mnt/volume_nyc3_01 ext4 defaults,nofail,discard 0 0' | sudo tee -a /etc/fstab

and then changed the permissions on /mnt/volume_nyc3_01 as follows

chown -R mysql:mysql /mnt/
chmod 777 /mnt

everything is properly mounted

Filesystem     1K-blocks     Used Available Use% Mounted on
tmpfs             400592     1060    399532   1% /run
/dev/vda1       25215872 17595240   7604248  70% /
tmpfs            2002948        0   2002948   0% /dev/shm
tmpfs               5120        0      5120   0% /run/lock
/dev/vda15        106858     7304     99554   7% /boot/efi
tmpfs             400588        4    400584   1% /run/user/1001
/dev/sda          376776       32    340048   1% /mnt/volume_nyc3_01

but I get a permissions error

2023-09-23T00:59:53.320444Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.34-0ubuntu0.22.04.1) starting as process 2638
2023-09-23T00:59:53.329099Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
mysqld: Can't create/write to file '/mnt/volume_nyc3_01/ibKZcmv4' (OS errno 13 - Permission denied)
2023-09-23T00:59:53.343516Z 1 [ERROR] [MY-012576] [InnoDB] Unable to create temporary file inside "/mnt/volume_nyc3_01"; errno: 13
2023-09-23T00:59:53.343550Z 1 [ERROR] [MY-012930] [InnoDB] Plugin initialization aborted with error Generic error.
2023-09-23T00:59:53.343582Z 1 [ERROR] [MY-010334] [Server] Failed to initialize DD Storage Engine
2023-09-23T00:59:53.343809Z 0 [ERROR] [MY-010020] [Server] Data Dictionary initialization failed.
2023-09-23T00:59:53.343863Z 0 [ERROR] [MY-010119] [Server] Aborting
2023-09-23T00:59:53.344673Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.34-0ubuntu0.22.04.1)  (Ubuntu).

here’s the directory with permissions

drwxr-xr-x 19 root  root  4.0K Sep 23 00:02 **..**
drwxrwxrwx  3 mysql mysql 4.0K Sep 23 00:56 volume_nyc3_01
drwxrwxrwx  3 mysql mysql 4.0K Sep 23 00:57 .

apparmor is not running. I’m out of ideas. Anyone have a suggestion?

Thanks.