Staying on an old and unsecure OS sure is a solution, but it's incredibly fucking stupid.
At least you could install Linux and use an old Windows version inside a VM instead of running a vulnerable system on bare metal. That way you can still use Windows when you need to.
How are you planning to deal with the removal illegal content?
I like the idea of a decentralized web but when I tried ZeroNet I saw some despicable stuff on there.
If you do nothing about such content then your platform lost likely will end up as a pedofile haven.