The viewing time is the total of the entire time the video has been viewed and will increase even if the same person watches it twice. However, if YouTube considers this to be a false view, the view count and watch time may also be removed later. Yes, I think the viewing time will increase. If the same person watches the video over and over again, the viewing time will increase.
But don't think that you can play with the algorithm to make your video show more, like this. I'm sure YouTube has taken this scenario into account. Afterwards, you can increase your views by watching it for at least 30 seconds. However, YouTube will prevent you from adding new ones after you've watched it four to five times in 24 hours.
Unfortunately, the views of a YouTube video are not like the views of your Instagram story, you can't see which users are watching your videos. No, it doesn't increase views, since YouTube also keeps track of the IP addresses from which a video is viewed. YouTube uses the device's IP address to determine if the view comes from a user who wants to watch a video. Because, even if you meet the condition of a viewing time of at least 30 seconds, a view from the same IP address makes YouTube suspicious of you.
If the video is private, deleted, or doesn't appear in the list, the viewing time won't increase even if you watch it for hours.