Hi, you are totally right, for both of your points :

• for the time jump, the idea around it was to allow viewer to quickly consume the replies on a video, while still providing a context on the main video but this should jump only on this specific usage, as discovering a video by the video replies let on it. Now as it is implemented is more disrupting the viewing experience than anything else. So thanks for bringing this on the table :)
• And for the autoplay, I'm myself lacking at lot this feature, and we had deep talk about it with one of our community member from our discord channel, and I think his view on this is quite nice actually. To wrap his idea : autoplay should be default on all replies on the main video, then if the creator of the main video replied to a reply, then it should auto play. If other people replied to a reply , the user would have to click on this 2d level reply to play it.