Aforementioned, both are good and worth paying for. If your actual wallet only allows you to pay for one, i'd pay for a good, reliable, fast VPN, and use a free good alternative for antivirus software like Avast tweaked for maximum security.
I personally see the value of a VPN to be considerably more desirable given the advance in default security of Windows (fully up to date and patched), MAC, Linux, IOS and even Android who has good free options.
However, I'm currently a paid AV subscriber and a VPN subscriber because I don't trust Windows Defender on some partners computers. (NORMIES)
The untold reason people actually want VPN would be:
more privacy (hide your IP from certain organizations or people)
access content which ISPs like to block (you could use free VPN for that but than you lose privacy)
The told reason people actually want VPN would be:
access internal networks externally (in some cases. Mainly for company use)
AV's job on the other hand is to stop virus before the patch comes out.
If your system is up to date and still supported by the vendor you are most likely not in need of antivirus. Just trust bare minimum of the websites.
Both protonVPN and Windscribe VPN separate their free users into specific "free" servers, and therefore their IP addresses are more likely to be blacklisted as compared to other paid servers. This doesn't really affect your privacy but you'll definitely run into some issues in the long run
Because many of us use a combo of both, not many seasoned members here will forsake a VPN or Security software for the other.
It's like asking what leg I want cut off, left or right ? ... I say keep both.
The "Either Or" option is not a healthy one. For example I run Security software "and" AirVPN.
I bet more would vote if the options were a little more realistic