It's strange, I shared the link in another community and the video preview appeared there, but not here. It's probably some administrator setting. My YouTube channel is Black Jack GS. You can find the video I shared there, and thank you so much for commenting. Since the community seems a bit deserted, I thought there weren't any active members, haha.

I think the concern is the multiple accounts and frequency of reposts.

When you use a few different accounts to share the same content, people who don't want to see it will have a hard time blocking it. When someone posts the same content too often in a short period of time, people start to downvote the subsequent posts.

You're absolutely right, I think I should record the before and after of the mechanical work to compare, but I still have more improvements to make, I'll record those as well for reference. Thanks for commenting, really!