SSH into private machines from anywhere using Cloudflare Tunnel

If they upgrade to premium tier, set up your virtual server then. Your total cost, $0 for the duration it's free + $4 * the rest is still lower than $4 * lifetime, and the cost for switching is only going to be marginal.

I get the thought, you can build something now that is guaranteed to have a fixed cost, or you can risk going with a free product that might surprise you, causing you to rush to replace the solution with a tight deadline.

Just look at all the people panicking with the free Google Workspace shutdown.

I can use virtual server for many things (backup, vpn, webservices...) not just port forwarding.

Cost of my time for reading contract and learning new proprietary tool is not worth it for several years.

Cloudflare is arguably better from big tech. But cost of deployment some binary package on confidential server, keeping up with their marketing bs, etc is simply not worth it.

If I have to spend an hour or two setting up each solution, I could pay $4 a month many years before I'd feel like it was worth doing that twice. You're not wrong, but I would gladly pay the monthly to only have to set it up once.