Installation on Synology nas

i am not able port forwarding external due ISS providor and bitwarden.xxx.synology.me is not accesible on chrome and and im getting the following warn

This browser requires HTTPS to use the web vault Check the Vaultwarden wiki for details on how to enable it  

my plan to run Waultwarden only on local without any external access and livesync with chrome ios and android clients, ( i will be on local most of time localhost via Tailscale )

When this is the case, is there an estimated way for my wishes to come true?