Nobody is going to help you "from A to Z" for free. The streaming services (like Spotify) do have services for artists if you seek them out and pay.
Definitely, do register copyrights as soon as the recordings are completed. If you're in the US, the hardest part is understanding the arcane interface of the Copyright Office website. Then, you pay your fee and upload your audio.
You don't need to call (or email, text, etc.) a label. You can try, but I wouldn't wait for a label's help to proceed.
As long as you can get your audio to meet the technical and quality standards of the streaming services, you can do the rest yourself, but it will still cost some money.
You could simply post the tracks to Bandcamp, and they will be "out there", but the only people aware of their existence will be the ones you tell and the only way for people to hear them is on the Bandcamp website or app, or as a download.
You could also use a digital distribution service to get the tracks onto the major streaming and download platforms. Some of them have affiliations with mastering houses (whose services I suspect you can benefit from if you can afford them). FWIW, I have used CDBaby for more than 20 years. They used to be the only one doing what they do, but there are many more choices now. You will pay a flat rate to get it distributed and you will collect a substantial share of the proceeds, but keep in mind the proceeds from streaming are vanishingly small.
Some additional notes:
You will probably need album cover artwork. Read the technical and content requirements of streaming services before you expend effort creating it.
The digital distribution services will help you collect royalties (small as they are) from radio, satellite radio, YouTube, etc.
In a home studio you are probably unable to accurately assess the sound overall. It may sound good to you there, but in other acoustic environments it may not. One of the benefits of mastering is the controlled listening environment of the mastering studio.
Without knowing you or your music I can't say for sure, but I suspect you would also benefit greatly from critical listening by someone knowledgeable and trustworthy, yet independent of the project. There is always something that can be improved, and better to do it now when it's only your labor at stake.
Even once your recordings are on the streaming services, it's still incredibly difficult to get anyone to find them, unless you already have some following, e.g., from live performances. (I suspect you don't have this if you're doing everything yourself.)