After starting script on my local host, it disconnects from anything

[Ciugam]

Hi, I like the idea of the repo.
My goal is (example):
Smartphone/PC/... (tailsc.) --> home local server (tailsc.-exit node) --> mullvad -> internet

I've configured IPs of tailnet (included local server) and removed ipv6 flags in config.
I use ufw for other things, but I didn't touch it for this thing.
nftables already installed, and mullvad set up correctly.
I use this machine as exit node and subnet for tailscale.
When I start the script, the host disconnects and I lost all connections. I can't ssh locally, neither on tailscale.
Suggestions? Thanks in advance.