Does Youtube accept 10bit uploads? If so, what codec should I use?
Youtube converts files in two main containers, flv and MPEG-4 AVC (or h.264). For everything below 720p, youtube usually switches to flv, for everything above it uses h.264.

Your file will get compressed by youtube's own bitrate indeed, but upping the bitrate in the encoder will still give you vast improvements in image-quality.
You need to keep in mind that the file will get compressed about three times in your case. When the camera records the image, it compresses it according to the filetype and codec it is set to. Then, after editing, the file will get rendered and compressed furthermore. And at last, youtube will also convert and compress your file.

So, to minimize loss of quality, it's worth considering upping your bitrate of the encoder you use (Adobe Media Encoder, Premiere, After Effects, etc.), since this is the only thing you could change as of now. A bitrate of 25-30 should be what you want. If file-size is not to be considered, I would even recommend pumping it up to about 50. Also, make sure to tick the "use maximum render-quality" when you're using adobe's encoders.

The only limit youtube has for uploading is 124gb file-size if I remember correctly. It's a value videos should never reach tho.