Yeah, and all of that metadata handling can be properly moved to someone you either trust more or someone who doesn’t have enough info to connect it to you. DNS over https, VPNs and TOR exist. All of these systems are secure, but can be compromised by someone with direct on premises server access, if they’re skilled enough.

Open source client only.

Not really. Your IPS cannot look at the contents of your server. Any VPS provider can look at the contents of your RAM, and in turn, break any encryption you use on the device.

Solid color square is probably the only good solution. Blurring/pixelation might work for photos of things that were never photographed before or after. There are ways of reconstructing the original if you have multiple blurred photos of the same subject, and even the current generation of AI is pretty good at guessing what the blurred image might show.