I’m not sure how relevant some of this is today, but here goes: one of my close friends worked out a deal with the high school we attended to do work study in Nashville. He got to be the low man on the totem pole working with some of the top players back in the day.
He did go to Carnegie-Mellon for music for a couple semesters but found it more theoretical than practical. Eventually, he worked his way into the LA studio scene and got gigs. It took years but he managed to work with some top talent and got credit.
This was in an era when there weren’t "schools" to train engineers. People learned on the job and got their knowledge from people with more experience. They might start out low- working for almost nothing but eventually, if they were committed, they got opportunities.
Today, it is a whole different thing. I’m in Austin, tons of musicians who are not making much money; lots of studios. The community college, which is very good, has training in studio tech and recording technique. I’m not suggesting that’s an answer but there are resources. The trick to me is to create a network. I talk to guys at Berklee, UCLA and other schools- most of them are generous and glad to help. The days of the big expensive, well-outfitted studio are pretty much gone- though there are a few.
You have to be willing to talk to people, to reach out, to travel and to apprentice, for lack of a better word. We tend to lump all of this into "engineering" but there are different facets: the recordist, who sets up mics and knows how to set up the room and musicians to capture the sound, the mixers, who know how to take the tracks and make them sound best, the mastering engineers who know how to take a mixed down master and turn it into something that resembles the master.
Only a few studios work with tape these days.
Several questions- where are you located and what resources are available to you? Chances are a working commercial studio is going to have better equipment than you can afford. Nothing wrong with learning on your own, but there is something to be said for the more traditional apprenticeship and seeing how the greats put together a record. Sadly, some of them are now gone. But there are new producers, mixers and engineers. One of the guys I know -- the son of a friend-- owns a venue here in Austin but is spending most of his time mixing commercially successful records Success builds on itself and the knowledge you accumulate is invaluable.
How you pay the rent and make a living while you are learning the art isn’t easy.
But there are opportunities if you seek them out. Austin has very little music business "infrastructure" compared to Nashville. You may not like the music they are cranking out there these days, but they are pretty busy. Engineers can get work when players are scraping by.
Hooking up with notable people who can act as mentors is my best suggestion.
PS: composition is entirely different from engineering. The money in the business is publishing. Songwriting is key. If you can write good songs, you can get them produced. What you give up in the process is the stuff the lawyers deal with, so sooner or later, you'll have to deal with that, but if you aim is songwriting, I'd concentrate on that. Sure, you can use a home studio to compose. But don't confuse what you are engineering with the compositional efforts. Two entirely different things. There is no "magic bullet" to "breaking through" but I'd value a good songwriter over most any other aspect of the art. I say this, having worked as counsel to a lot of major players over the decades and seeing how they fared as time wore on.