4k Monitor, 1080p gameplay

Hi, I am using a 4k monitor. However my system is not powerful enough to play games in 4k at the settings i would like. So i run games in 1080 and use the 4k for movies. Now the issue is when i play league in 1080 on my 4k screen. the scaling is completely out, now i can adjust the hud, chat, death recap and mouse scale. but the combat text is bigger than my champion, the kill announcment fills half of my screen and the items in shop are just massive, is there any way to adjust the scaling on these elements? tia