I did disable all caches, cleared them from backend, then manually deleted all the rest files in /cache/smarty.
Also disabled cloudflare (put it in dev mode) and used chrome in incognito mode to try and use OPC. Then tried ctrl+r and f5 to probably refresh it's cache if it's stuck.
No luck with all this.
This is on php7.1 if it makes any difference.
Tried php 7.2 - works just the same - error
7.3 - db link error