UPDATED May 5:
I apologize to the forum for mixing two different problems. They are unrelated.
Problem #1: User error. I thought I was using a class 6 SD card but I was wrong. The yellow "!" indicates a pathologically slow card. Upgrading to a class 10 resolved this problem.
Problem #2: UNRESOLVED. Red battery indicator comes on prematurely. On a fresh charge, it'll turn red after recording for a couple of minutes. On a partially drained battery, it turns red immediately upon entering movie mode or pressing the record button. Turn the camera off and then right back on in "still" mode and it shows full charge and works fine ... until trying to shoot video. I have not precisely measured recording times but it'll record for at least 20 (maybe 30?) minutes while flashing red.
Check out Nikon's model in the same price range. The zoom isn't nearly as good (120mm quivalent, compared to 500) but Nikon's low-end aperture is better (f/1.8 compared to f/3.5). The Nikon's sensor is bigger (1/1.7" vs 1/2.3"). Nikon has a RAW option, but the write time seemed very slow to me. In most other ways - excluding battery life, obviously - the cameras are pretty comparable. One thing I noted with the Nikon versus the Canon, the Nikon's photo quality was much better to begin with. It looks like Canon is doing some aggressive compression that leaves the photos feeling a bit crunchy for my tastes. Had Canon been a little more receptive with their customer service, I probably would never have noticed.
12/05/2023: New firmware updates are available.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.