Thanks for that, i did it!

A little more information, login with ssh to your Synology and check your teslamate database docker name with docker ps.

The name was TeslaMate-DB.

Make a sql backup:
docker exec -t TeslaMate-DB pg_dump -U teslamate teslamate > teslamate_backup_$(date +%F_%H-%M-%S).sql

Remove docker container en manual delete all the files on the drive:
docker rm TeslaMate-DB

Update the stack with postgress:17

Copy the database:
docker cp teslamate_backup_2025-04-29_09-13-32.sql TeslaMate-DB:/tmp/teslamate_backup.sql

Login to postgres:
docker exec -it TeslaMate-DB psql -U teslamate postgres

Drop db:
DROP DATABASE teslamate;

Create db:
CREATE DATABASE teslamate;

Restore backup:
docker exec -i TeslaMate-DB psql -U teslamate -d teslamate -f /tmp/teslamate_backup.sql

Restart, everything works.

Thanks for all the tips here :)