What format are you recording in? 1080P 30fps? 24fps? And what are you export settings?
YouTube compresses whatever you upload to it. For 1080P 24/30fps footage their recommended Bitrate is 10mbps. For 50/60fps footage it is 15mbps. https://support.google.com/youtube/answer/1722171?hl=en
Personally I export a bit above their bitrate. It results in significantly larger files but I feel like less is loss in YouTube's compression on their end with that.
For 1080 footage I export at 18-20MBps, kind of on a whim which I pick. For 4k Footage I output at around 45-50 MBps as their 4k 24/30 Bitrate is 35-45.
Basically when you upload to YouTube you will ALWAYS lose some quality. Produce a better product to send to them and you will have less chance of it ending up bad. That said it is of course a "law of diminishing returns" thing. If you crank up the bitrate to even what your camera is recording at for your export, you won't see a massive improvement once its on YouTube, but you will have a massively sized file.
One thing I've noticed is 4k footage just looks crisper on YouTube(duh). By that I mean I feel that since I switched to 4k, my uploads don't seem to lose as much in the upload process as my 1080P footage used to. I too would see some loss in the uploaded video, but the 4K seems truer to what I produced.