Official docker image with subnet routing

First off: I am in love with tailscale and am using it to solve man problems.

One of my first solutions (at my home) is the tailscale plugin in homeassistent. It works like a charm with subnetrouting enabled I can access the whole local network there.

For another site (parents) I want to install tailscale via the official docker image tailscale/tailscale:latest

I figured out how to make it non ephemeral via the environment variable

TS_STATE_DIR=/var/lib/tailscale

But I am stuggeling makeing a subnet routung anouncement:

What environment variables should I set?

ROUTE=10.0.0.0/16

or

TS_ROUTES= 10.0.0.0/16

or maybe

TS_TAILSCALED_EXTRA_ARGS="-accept-routes --advertise-routes=10.0.0.0/16"

Sorry for asking such a basic question, but found no clear cut example and only get one or two trials per week to test a new config.

Additionally: Can I somehow advertise an exitnode using the environment variables?

TS_EXTRA_ARGS=???
TS_TAILSCALED_EXTRA_ARGS= ???