How to get first 100 users with no marketing skills?

Unfortunately, as you are learning, this is 100% backwards. Writing something that is commercially successful starts by identifying a potentially commercial product.

In other words, you need to start by Marketing, not programming. You're looking for 3 things;

A market you can reach; That have money to spend; That are prepared to spend money to make some pain go away.

It might be obvious that a market might exist (say something that makes govt more effective) but selling to govt requires enormous resources you don't have.

It might be obvious a market exists (a tool for refugees to apply for aid) but they have no money to buy anything from you.

It might be obvious a market exists (trips to the moon) but you can't build that.

Once you have found a market you can reach, who have some money, and are willing to spend (perhaps with a deposit) then (and only then) should you start coding.

Commercializing stuff you have already made is hard because the product was tailored to a specific user, and he already has it (aka you).

1. Just do split screen videos where you talking head with slides on the other, and read off the slides.

2. Record in segments, with a full reset between each segment. Makes editing really fast.

3. Don't stress about small mistakes. People are into authenticity, it's ok.

Lighting/"studio" design is still an art, but you can get something set up in a day or two. The harder part is coming up with good video ideas, and doing a compelling title/thumbnail/hook. That's a rabbit hole.