At my job, we run goharbor.io and use its Replications feature to do just that.

It said "smart", not "morally right".

Gitlab at work, because, well, it's there and it works just fine.

Forgejo at home, because it's far less resource hungry.

In the end Git is a) a command line tool for b) distributed working, so it really doesn't matter much which central web service you put in place, you can always get your local copy via git clone REPO.

Try goharbor.io, that's what I use. I think (but I'm not sure) that Forgejo/Gitea and Gitlab can also cache images.

This is my day job, so I'd like to weigh in.

First of all, there's a whole community of GLAM institutions involved in what is called Digital Preservation (try googling that specifically). Here in Germany, a lot of them have founded the Nestor Group (www.langzeitarchivierung.de) to further the case and share knowledge. Recently, Nestor had a discussion group on Personal Digital Archiving, addressing just your use case. They have set up a website at https://meindigitalesarchiv.de/ with the results. Nestor publishes mostly in German, but online translators are a thing, so I think you will be fine.

Some things that I want to address from your original post:

• Keep in mind that file formats, just like hardware and software, become obsolete over time. Think about a migration strategy for your files to a more recent format of your current format falls out of style and isn't as widely supported anymore. I assume your photos are JPGs, which are widely not considered safe for preservation, as they decay with subsequent encoding runs and use lossy compression. A suitable replacement might be PNG, though I wouldn't go ahead and convert my JPGs right away. For born digital photo material, uncompressed TIFF is the preferred format.
• Compression in general is considered a risk, because a damaged bit will potentially impact a larger block of compressed data. Saving a few bytes on your storage isn't worth listing your precious memories.
• Storage media have different retention times. It's true that magnetic tape storage has the best chances for survival, and it's what we use for long term cold storage, but it's prohibitively expensive for home use. Also, it's VERY slow on random access, because tape has to be rewound to the specific location of your file before reading. If you insist on using it, format your tapes using LTFS to eliminate the need for a storage management system like IBM Spectrum Protect. The next best choice of storage media are NAS grade HDDs, which will last you upwards of five years. Using redundancy and a self correcting file system like ZFS (compression & dedup OFF!) will increase your chances of survival. Keep you hands off optical storage media; they tend to decay after a year already according top studies on the subject. Flash storage isn't much greater either, avoid thumb drives at all cost. Quality SSD storage might last you a little longer. If you use ZFS or a comparable file system that provides snapshots, you can use that to implement immutability.
• Kudos for using Linux standard tooling; it will help other people understand your stack of anything happens to you. Digital Preservation is all about removing dependencies on specific formats, technologies and (importantly) people.
• Backup is not Digital Preservation, though I will admit that these two tend get mixed into one another in personal contexts. Backups save the state of a system at a specific point in time, DigiPres tries to preserve only data that isn't specific to a system and tends to change very little. Also, and that is important, DigiPres tries to save context along with the actual payload, so you might want to at least save some metadata along with your photos and store them all in a structure that is made for preservation. I recommend BagIt; there's a lot of existing tooling for creating it, it's self-contained, secured by strong checksums and it's an RFC.
• Keep complexity as low as possible!
• Last of all, good on you for doing SOMETHING. You don't have to be perfect to improve your posture, and you're on the right track, asking the right questions. Keep on going, you're doing great.

Come back at me if you have any further questions.

400 staff German state institution, Windows desktops are standard, but you can get a supported and standardized Linux Mint installation provided by IT on your personal computer upon request. A few dozen people do. We also provide some 150 publicly accessible PCs for research in or brach locations, all of which are Mint as well. And IT staff is allowed to install any system on their hardware they want, no questions asked; many run Linuxes. Linuces. Linnixees.

Always has been. insert meme of astronaut shooting the other astronaut in the back of the head

EDIT: spelling

And that unit shall be called "1 milliweasel".

"We're out of BORT license plates!"

Very true! And once you've done it for a while, you start to notice other cachers by the way they are awkwardly standing in unusual places trying to look inconspicuous.

My wife has gained roughly 60 kg since I meet her many years ago, which some might see as that kind of limitation, but you know, I don't even see that when I look at her. She is smart as fuck, a great engineer, a wonderful mother, and just overall the better half of me. It's just so easy to love her, and I would never even consider leaving her for looks. We all have our imperfections, but that's not to say we're not worthy of love. Oh yeah, I'm a terrible smart ass, overweight, impatient, not a great father, and I don't communicate very well. Beats me what she sees in me.

With a username like this, I'd give all my hosts and servers moon names. Like the moons of Jupiter (Io, Europa, Ganymede, and Callisto).