What's your backup strategy?

Sure, I won't post exactly what I have, but something like this could be used as a starting point:

#!/bin/bash
now="$(date +'%Y-%m-%d')"

echo "Starting backup script"

echo "Backing up directories to Wasabi"
for dir in /home/USERNAME/Docker/*/
do
    dir=${dir%*/}
    backup_dir_local="/home/USERNAME/Docker/${dir##*/}"
    backup_dir_remote="$now/${dir##*/}"

    echo "Spinning down stack"
    cd $backup_dir_local && docker compose down --remove-orphans

    echo "Going to backup $backup_dir_local to s3://BUCKET_NAME/$backup_dir_remote"
    aws s3 cp $backup_dir_local s3://BUCKET_NAME/$backup_dir_remote --recursive --profile wasabi

    echo "Spinning up stack"
    cd $backup_dir_local && docker compose up --detach
done
aws s3 cp /home/USERNAME/Docker/backup.sh s3://USERNAME/$now/backup.sh --profile wasabi

echo "Sending notification that backup tasks are complete"
curl "https://GOTIFY_HOSTNAME/message?token=GOTIFY_TOKEN" -F "title=Backup Complete" -F "message=All container data backed up to Wasabi." -F "priority=5"

echo "Completed backup script"

I have all of my stacks (defined using Docker Compose) in separate subdirectories within the parent directory /home/USERNAME/Docker/, this is the only subdirectory that matters on the host. I have the backup script in the parent directory (in reality I have a few scripts in use, since my real setup is a bit more elaborate than the above). For each stack (ie. subdirectory) I spin the stack down, make the backup and copy it up to Wasabi, then spin the stack backup, and progress through each stack until done. Then lastly I copy the backup script up itself (in reality I copy up all of the scripts I use for various things). Not included as part of the script and outside of the scope of the example is the fact that I have the AWS CLI configured on the host with profiles to be able to interact with Wasabi, AWS, and Backblaze B2.

That should give you the general idea of how simple it is. In the above example I'm not doing some things I actually do, such as create a compressed archived, validate it to ensure there's no corruption, pruning of files that aren't needed for the backup within any of the stacks, etc. So don't take this to be a "good" solution, but one that would do the minimum necessary to have something.