This might be a good use case for distributed storage (IPFS?).

Instead of hosting this directly on my computer, it would be interesting to have a setup where the archiving is done via the service and I would just provide somewhere a storage space where the content would end up being mirrored (just to guarantee that my valuable things are saved at least somewhere, should the the other nodes decide to remove the content).

I would prefer this setup, because it would be easily accessible for me from any device and I would not need to worry about running some always available system. With some suitable P2P setup my storage node would have less strict uptime requirements.