I feel like everyone (myself included) thinks "Oh, that company/industry has their shit together", spoiler: they don't. One lesson I have to keep reminding myself of and relearning is a large company (even successful ones) doesn't not immediately equate to knowing what they are doing. Imposter syndrome is a huge issue inside the tech industry, I imagine it's even worse for the people on the outside looking in.
Maybe a part-time web development job would work for you? Get your feet wet without having to go full-time right away.
My comments about certifications really boil down to "Don't expect a certification to result in a job or even better standing among other applicants". Being someone who is enjoyable to talk to/work with goes way further in my book. I'll take a "1x" programmer that's easy to work with over a "10x" that's a jerk or has no social skills. Also your "self-taught" skills are probably a lot better than you are giving yourself credit for. I'd bet money you would do better than the majority of new CS grads when it comes to actually producing.
Looking into it, I 100% take my self-taught music skills and management for granted. Having had to work with all spectrums of artists from pop, hip-hop, male, female, young to old, the goal would always end up being how do we get this song completed to the best of our abilities and ready for worldwide release.
It’s a tedious process consisting of communicating and directing tons of people to achieve the unified goal even when they don’t see it.
I’m assuming in tech, there are similar environments like that.