The simplest would be renting a VPS I think.

I grabbed an Oracle free-tier many moons ago. The x86 one with 4 gig of memory I think? The arm have a much more core and memory but unless you go with Pay As You Go (PAYG) account ( need a one time refundable $100 credit) it’s virtually impossible to grab it.

My free tier account is sufficient as pure VPN for accessing stuff, you get 10 TB/month egress traffic. The downside is it’s Oracle, and you are at their mercy ( they can purge it without notice )

I never tried it because CGNAT but maybe Dynamic DNS could also solve this.

Other than that, Tailscale / CF tunnel etc are a fine solution ( for now )

Did you tried various cat subs? Jus the r/cat prob have enough traffic if you provide enough proof. Also try to DMs the mod.

Good luck