3600 was released in 2019. And it they was making it for at least 2 years.

Syncthing sync files, it is all does.

what exactly do you mena under subdomains? Any DNS provider will support adding NS entries for subdomains if you want to host you sub-zone somwhere, And any should allow you to use names with "." in it for "fake" subzone, like
a.subzone1 IN A x.x.x.x
a.subzone2 IN A y.y.y.y

you do not need passport inside Australia. But in other hand you still paying for driver licence/photo id.

HIkvision is great. Good value for money. Just do not use the app to configure them, use web gui. And yes, they need to be isolated from rest of network and the internet ( as pretty much any cameras).

Blu Tac?

Symphonium is another good mobile client.

Do not access volumes directly on filesystem. path may change. If you need access data on a volume just spawn temporary container an mount that volume.

Voted around 8am, they was still closed. I guess 8am is perfect time for a sausage.

Absence of Yaml is exactly biggest annoyance in modern HA. It just not configurable without million of clicks. Just try to apply same automation procedure to other set of devices. In text you just copy block, in GUI you have to redo everything from scratch.

Gitea is in same lightweight category.

Yeh, It is big fault in ActivityPub design that IDs are linked to domain name. Should not be a case. Some UUID + public keys will make it way more flexible and resilient.