Can't open my HTML5 build in Safari

I’ve been working on a project for a few months, with HTML5 being the only delivery platform. It works more or less ok in Firefox and Chrome, but there’s no way to make it work in Safari. When I tried to load it in Safari, I get this:

Expression (Value_GL_MAX_COLOR_ATTACHMENTS >= MaxSimultaneousRenderTargets || !FOpenGL::SupportsMultipleRenderTargets()) failed in D:/Build/++UE4/Sync/Engine/Source/Runtime/OpenGLDrv/Private/OpenGLDevice.cpp:749!
Check console for details.

I think it might be just M1 Macs, because a friend of mine loaded it in an older Intel Mac and it loaded fine. But still, there are a lot of people with M1 Macs already, so I would prefer this to load in every major browser.

Any idea what does that error mean? I pasted it on Google but it gives me posts from people that get something similar when they are trying to build for mobile, which I am not, or some other situations, and it’s never an exact match to my error.