Improper rendering at higher resolutions

[smiga0303]

First of all I want to apologize, I know this question must've been asked before but I don't know what to search for or what's it called.
Assassin's Creed: Bloodlines has... artifacts? that become increasingly pronounced as I up the rendering resolution.

1x: https://i.imgur.com/tCaprgp.png
4x: https://i.imgur.com/6QqT3yk.png
10x: https://i.imgur.com/n52XcRO.png

Can anything be done about this? I know non-native rendering always introduces problems. I've tried different combinations of texture scaling and filtering, but to no avail.
Thank you