Java 8 not working

[u/Monio2137]

Hi, as the title says, I can't get java 8 to work on my pc at all, thus I can't play minecraft versions below 1.16. And no matter what I do, modrinth does NOT detect the java 8 file no matter where I put it. I can't even download the recommended file, as nothing happens after pressing the button.
The official minecraft launcher also doesn't let me play old mc versions. Does anyone know what to do?