Extreme battery drain for VPN Clients - is there a better way?

[Android Central Question]

I recently signed up for a pretty well-known VPN provider, but after some time, its client seemed to be a really big battery hog (used like 1.5x times that of the screen). After looking at some XDA posts, I tried StrongSwan/Ikev2 client - it proved to drain even more battery.
Is this normal? A VPN runs all the time, but this still doesn't seem to justify this huge-*** drain. Are there better clients?

(for clarity, I'm asking about VPN clients (openconnect, ikev2, etc) not services/subscriptions)