… "HDMI capture #UVC" (#USBVideoCapture) https://www.bhphotovideo.com/c/search?q=hdmi%20capture%20uvc&sts=ma seems better search term than "external HDMI capture USB"
Needed to reread one of the reviews (of Roland UVC-01 USB Video Capture, UVC-01, 1080p60, US$ 218) to parse "AI" in the context as "audio input" https://www.bhphotovideo.com/c/product/1633695-REG/roland_uvc_01_usb_video_capture.html/reviews
Ooh, VGA input!
AVMATRIX Multi-Signal to USB 3.0 Capture, UC7018, $ 430, https://www.bhphotovideo.com/c/product/1891091-REG/avmatrix_uc7018_multi_signal_to_usb_3_0.html
— reported bad support in reviews of other items sucked the excitement.