As far as I know, no options exist for something like a local PeerTube instance without a proper server, without also having a domain name, so doing it locally is a bit complicated.

I’d guess the closest would be to have tabs open with videos you want to mirror, so you are a peer via webtorrent for those, but that is clunky, and I am unsure how well it would even work without having the tabs active.

But I am relatively new to this as well, so maybe someone else has some info I am lacking right now.