Building a site in a YMYL niche without any formal proof of EAT.

I am currently starting out with trying to build a website in the financial niche. I think I can provide some good insight on some topics and I research topics very in depth and am able to break down complicated topics to simple explanations.

My problem however is with EAT. I don't have a degree in the field or any formal proof of expertise, authoritativeness or trustworthiness. What can I do to increase googles perception of myself in those aspects?

So far the only thing I have thought about would be to write a guest post on another site, however that would be nowhere near enough.

Does anybody have some ideas or tips?