I disagree with the other poster. Your niche is not necessarily super small niche, the toy car restoration. This kind of content can fall into those "satisfactory video" kind of content. People love watching the dedication, the process and the result. It's satisfying. I personally LOVE it. Now let me show my love to such creators. This gonna be a bit long.
It's just like the speed painting or drawing, the wood carving, woodturning and so on. Right now, you may not have the pre existing audience set but once the ball is rolling, your content will reach much wider and cross section audience.
The problem with Youtube is, it doesn't matter how good your content is, they won't promote it until you promote it first... by yourself, to break the barrier entry.
There are various options to do that, depend on many things. But whatever it is, it should be about building your audience base. You do the right thing by posting it on socmed and you're doing good as you got positive comments.
YOU GOT TO BE PATIENT. The first step is always the hardest, it's baby step. You'll fall a lot more than you walk. BUT HERE IS THE THING. It will only take one momentum, and when it start rolling, you'll grow exponentially. That's how Youtube works.
YOU GOT TO BE PATIENT. No one knows when will you get the lucky chance, maybe it will take weeks, months. Just keep building your audience, little by little. It's always been like that, when you build a channel. That's how it works.
But if you just can't wait, then spend some money. Make a stunning short video compilation of best scene of your work so far. With sick soundtrack and slick animation. Pay someone if you can't make it. Then promote the stunning video using Google Ads. Buy some cheap threshold acc. Or FB ads, etc.
The reason is simple. Any channel or videos need to have certain amount of "user history", only then Youtube will start showing the videos on their outlet be it on Home page, Search Page, Suggested bar etc.
There are too many videos on Youtube, there's limited promotion spaces. Hence, the barrier entry. How algo do the ranking which one to promote in each of its outlet? "User history" on your videos or channel. You can translate it into CTR, Retention, Engagement, Cowatch, etc. You got to build this. Or you can fake it.
But I will stop right there as for now. Unless you know what you're doing, just don't. Unless you know how to "clean" those shitty traffic or engagements, it would be just a waste of money.
In short: 1. Do it yourself, be patient, socmed is good, your time will come, just be patient. 2. Promote using Google Ads, FB Ads etc. 3. Deal with the shitty SMM.
Good luck, my friend.