As far as i understood tailscale funnel its just a TCP-tunnel.
So you handle TLS on your own system, which makes sure tailscale cannot really interfere.
If you already trust them this far, might aswell do the same with a VPS and gain much more flexibility and independence (you can easily switch VPS provider, you cannot really switch tailscale funnel provider, you vendor-locked yourself in that regard)
I'd connect the VPS and your home system via VPN (you can probably also use tailscale for this) and then you can use a tcp-tunnel (e.g. haproxy), or straight up forward the whole traffic via firewall-rules (a bit more tricky, but more flexible.. though not that easy with tailscale.. probably best to use TCP-tunnel with PROXY-Protocol).
This way you can use all ports, all protocols, incoming and outgoing traffic with the IP-Address of the VPS.
Tailscale might even already have something that can configure this for you.. but i dont really know tailscale, so idk..
And as you terminate TLS on your home-system, traffic flowing through the VPS is always encrypted.
If you want to go overboard, you can block attackers on the server before it even hits your home-system (i think crowdsec can do it, the detector runs on your home-system and detects attacks and can issue bans which blocks the attacker on the VPS)
And yes, its a bit paranoid.. but its your choice.
My internet connection here isnt good enough to do major stuff like what i am doing (handling media, backups and other data) so i rent some dedicated machines (okay, i guess a bit more secure than a VPS, but in the end its not 100% in your control either)
To be fair, any proper VPN setup that only relies on the routing table like this is flawed to begin with.
If the VPN program dies or the network interface disappears, the routes are removed aswell, allowing traffic to leave the machine without the VPN.
So it is already a good practice to block traffic where it shouldnt go (or even better, only allowing it where it should).