I am finding I lose some video quality when I upload to YouTube even if I upload the RAW files. I am uploading direclty from my computer, not changing anything in the video. Does anyone know why this happens? I know the settings are important when you upload to YouTube but as I said, I am having this issue even with the raw footage which I am not adjusting at all. I am shooting 1080P 30fps and I am making sure I select 1080P when I go onto YouTube. I also have waited at least a day to check the video.

Youtube always drops the quality a bit but lately due to bandwidth saving they have been pushing that harder as it was requested by the EU.  You could try Vimeo they don't hurt the quality as much.

Depends what you watch them on, if you use the Youtube app there is a cog you can click on to change the bitrate, it normally defaults to 480 I think

Google, who owns YouTube, converts uploaded video to their preferred file format automatically. This is the biggest reason for the loss of overall quality. Uploading from a computer and not your mobile device, as you are wisely doing already, helps too. Government requested restrictions on bandwidth is meant to lighten the burden on ISPs due to the popular use of streaming television services, like Netflix, Amazon, and could slow your upload speeds but doesn't change a given upload's quality.