Uninstalling

Stop it, or remove every trace.

stop Talos and keep the data (start it again later with docker compose up -d)
docker compose down
remove it completely: this DELETES the database and Terraform state
docker compose down -v
cd .. && rm -rf talos                     # the folder, with .env
docker image rm talosfleet/talos-backend talosfleet/talos-frontend
down -v deletes the data volumes. Take a backup first if there is anything you might want, and keep the .env with it.

A trial (--eval) has its own command that removes everything, and only the trial: remove-talos-eval.sh (remove-talos-eval.ps1 on Windows) in its folder. On a cloud server installed by the start-up script, also delete /etc/profile.d/talos.sh and /var/lib/talos-installer.