I’m in the US but this should still apply to the UK
Is usenet and debrid safe to use without a VPN in the UK?
Yes, as long as your provider offers SSL encryption. If you’re using SSL encryption, the ISP can see what servers you’re connected to but not what data is being transferred and that should be enough protection. If there isn’t an option for SSL, you might want to use a VPN.
From what I understand it’s cheaper to use a VPN than have debrid + usenet + private indexers but I am not sure.
It is cheaper, but availability and speed are what you’re paying for if you sign up for a usenet provider.
I’ve been using both usenet and torrents for the past few years and never gotten a complaint. Usenet is my main source of everything. Only my torrent client itself is behind a VPN. All the arrs are unsecured and SABnzbd uses the SSL port for my usenet provider.