WiFi still greyed out after replacing antenna - Next steps?

@gigabit87898 is most likely correct on board repair. Sounds like your wifi ic needs replaced or reballed. That has been the only reason I have found so far for greyed out wifi.

There are components surrounding WiFi ic to check as well, but either way would require Micro Soldering repair.

Check out this video: https://youtu.be/S91fukLKZcU

Thanks for the help @teetopp

@gigabit87898 @teetopp Think it's more than likely the wifi IC. I'm not specialist with these but do you think it'd be possible to replace this IC if I buy a new one as well as flux and a heat gun? Or is it a hard procedure that I should avoid

Personally, I would recommend a professional Micro Soldering Tech to do it. There are several things that could go wrong for a beginner from overheating, Tearing pads, knocking off other components, etc...

And... it may not be the Wifi IC, it could be one of the components on that circuit and a professional would be able to diagnose that before changing the IC.

You can look for local repair shops, call them and price it, or even look through the PRO ads here on Ifixit and find one that you could do a mail in repair :)

I agree with @teetopp. This is not the kind of thing you want to learn with when you still value your phone. If you want to do it yourself, buy a bunch of dead phones and practice, practice practice. Then try it again on a working phone before ever touching your own device.