I have been using cheap Endoscope Cameras from Amazon, and I always keep an extra on hand as a spare. Video quality could be better, but it gets the job done. Not too bad for under $20.00. My new Bambu A1 arrived a few days ago, and the built in cam just was not what I am used to seeing. I was inspired by an ESP32-Cam mount by @ElJeffe, and adapted my Artillery SideWinder X2 endo cam mount. Here is the result. I highly recommend printing with PETG. In my example, I used Translucent Aquas by Atomic Filament. If using multi-color, I recommend printing each part on their own plate. Enjoy being able to watch up close.

Update:  I purchased a new autofocus endoscope, here.  Cost is a little more, and the diameter was bigger.  I made a few changes to adapt. The result is uploaded. Same print profile as the smaller version. New video is uploaded showing external camera and the new autofocus endoscope.