It sounds like your ask is for a recommendation to back up personal files from disparate locations to a server.

I use a self hosted Nextcloud instance for this purpose.

I have an arguably bad piece of advice, but one I hadn't seen in skimming the replies.

You could always install Windows in a VM. Libvirt and virt-manager offer a pleasant GUI experience so it's easy to do. If you give the VM a heavy resource allotment (while leaving a reasonable amount for the host) it should still perform well. The VM video driver is the only place you take a not insignificant performance hit, but for A/V manipulation I don't think it'll matter. Unless you use GPU based video encoding. In which case it'll be CPU bound now so slower. You can potentially do PCI pass through to your GPU but that adds complexity.

A big downside here is that as far as Windows is concerned, this is different "hardware" so it won't activate based on your physical device. As I recall, it only allows the use of one core while unactivated which is pretty much unusable. So a pretty hefty expense relative to a personal VM, I think. But it is an option.

You may want to pass through the audio so it's not reencoded. The top answer on this stack overflow article has an example. https://stackoverflow.com/questions/9913032/how-can-i-extract-audio-from-video-with-ffmpeg

And a copy/paste:

ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac

Relevant example, with afraid.org you can do it with a wget or curl command.

Sorry about your data loss.

I self host an instance of nextcloud on a headless machine in my home. It gives the benefits of typical cloud based services, but you control the storage. And if you sync with at least one other machine you have a full backup besides.

Of course no solution is perfect. This requires extra time, effort, and hardware. And having my data in one physical location has it's own risks. But I still prefer it.

So, something to consider if you or whoever is reading this isn't aware of that option.

Not an answer to your question, but rather an observation. Best to always assume you're being tracked and behave accordingly.