In what form? The private keys never leave the nodes, hence there shouldn't by any access per se (see https://tailscale.com/security/). Of course TS has insights into your networks, i.e. what servers it is installed on, what you connect to - so metadata.
But it still seems like they could flip that feature off if they got compromised. To remedy that, feels like they could support a preshared secret that they don't control / see being shared as a first step: https://tailscale.com/kb/1099/device-authorization/#generate...
Nothing in the Tailscale design has ever pointed to features that would guard your infrastructure from them.
Since Headscale exists, though, this problem is solved quite neatly.