I tried different font settings in the font settings and it didn't improve much (font hinting, anti aliasing, custom DPI settings, different font size)
The font is the default one which is Ubuntu Regular with font size set to 10
Sub pixel order is set properly to RGB Linux Mint xfce
Even when running windows in a virtual machine, the font rendering in it is miles ahead of what I got on my Linux setup!!!
Inter is great, I've been using it (TTF hinted) as my UI font for years and it renders very sharply. I'm on Debian and KDE Plasma
It's not made by Google though, it's this guy, Rasmus Andersson