I found this video quite interesting as I did all my VHS conversions to a DVD recorder many years back, and from there stuck those into my CD drive and copied them to my hard drive as CD format video files (.VOB I think they are). But yes, many had jagged lines on them, so quality was just not great.
This video not only shows an easier way with direct RCA-USB dongle capture, but also mentions why some such devices don’t scan well and which ones to rather go for. It certainly looks like I should try to reconvert my VHS tapes again, trying this advice.