I had this exact same issue when I first got my R6. I was honestly terrified of breaking the camera ports or buying some cheap knockoff that would overheat. After a lot of reading, I went with the Feelworld FW568 V2 5.5 Inch DSLR Monitor and it has been a really solid, reliable choice for my indoor youtube setup. Heres what you need to know about making it work:

• Get a small HDMI cable clamp. The micro-HDMI port on the R6 is fragile, and a clamp stops the cable from wiggling and damaging the internal board.
• You will need to buy NP-F550 batteries separately because it doesnt come with power.
• Make sure to set your R6 to clean HDMI output in the yellow menu so you dont record the camera UI. Its a decent, safe option that wont break the bank.

Re: "I had this exact same issue when I..." - totally agree that starting out with the R6 is a learning curve. I actually bought that same Feelworld monitor last year, but unfortunately, it was not as good as expected for my workflow. The 500 nits brightness struggled even in my bedroom with moderate window light, and the color calibration out of the box was pretty disappointing. I had issues with the reds looking way too saturated compared to what the R6 sensor was actually capturing. Since youre filming YouTube videos, you want something with accurate waveform monitoring and LUT support. I ended up returning it and spending a bit more on the Portkeys PT6 5.2 Inch 4K HDMI Monitor which goes for about $169. It has been a much better experience. Here is why the specs make more sense for the R6:

• 600 nits brightness and 100% of the DCI-P3 color gamut, so what you see actually matches your final footage
• Real-time 3D LUT monitoring via USB, which helps if you shoot in C-Log3
• HDMI input and output, letting you loop the signal to a transmitter or second screen later on Just make sure you buy a high-quality micro-HDMI cable too. The port on the R6 is super fragile and cheap cables wont hold the connection properly.

I've gone through at least four budget monitors over the years for my indoor setup, and honestly, you don't need to spend a fortune if you're just filming in your room. Outdoor brightness doesn't matter much inside anyway. What actually matters is having decent color accuracy and LUT support so you can see what your Canon Log footage will look like. I ended up grabbing the Portkeys PT6 5.2 Inch 600 Nit 3D LUT Monitor last year for about $130. It's cheap but does the job perfectly. Just keep in mind that these monitors don't come with batteries. You'll need to buy NP-F style batteries or a power adapter separately, which usually adds another $30 to $40 to your total budget. Keep that in mind before you buy.