Some of these you’re already doing, but writing a complete* list. *almost garuanteed not to be complete, suggestions welcome

1. Have everything behind the same reverse proxy, so that you have only one endpoint to worry about. Run it through ssllabs or similar to check your config.
2. On your reverse proxy, add one or more layers of authentication if possible. Many possibilities here: If one app supports client certificates, while another has limited capabilities, you could probably tie together something where IPs are whitelisted to the ither services based on that certificate auth.
3. Geoblock all countries you won’t be accessing from
4. crowdsec is pretty nice, this detects/blocks threats. kinda like fail2ban but on steroids.
5. if you use one of those 5$/month VPSes, with a VPN tunnel to your backend services, that adds one layer of “if it’s compromised, they’re not in your house”.

lastly consider if these things need to be publically avilable at all. I’m happy with 95% of my services only being available through Tailscale (mesh VPN, paid service with good enough free tier, open source+free alternatives available), and I’ve got tailscale on all my devices

As an “outside observer”, I think maybe you’re not seeing (what I believe is) the other guys viewpoint: What you are bringing up (photoshop has been possible already) is a core part of what he said from the start, and his point builds on top of that. So obviously he already knows it, and arguing about it disregards that his line of argumentation builds upon the basis we all agreed upon to be true until you brought it up as … contrarian? To his point. doesn’t seem like “old man yells at cloud” energy, more like “Uhm, achtually”