From my point of view, it´s not the best idea to "offer your music all over the place", which means, getting into any sync-agency and / or library you can. There are libraries, that sell songs for an average price of 20 or 30 bucks ... Imagine you want to make a living with it and you need ... say 3.000 a month. How many placements do you need each month to pay the bills?
Also that different companies have different kinds of clients. So you can work with a library that is mostly selling to guys that pay 30 bucks and want Royalty free music. At the same time, there are agencies, that sell to clients with way more money and you get cash from your PRO anytime your music is on TV ... so you get money for the license and then again from your PRO.
There is a company that takes 75% of the money from the sync license, plus 50 % of the publishing. And another taking 30 % from the sync license and zero from the publishing. Company one doesn´t move one finger to get you placements. They only put your music in a catalogue of 50.000 or more songs, why Company B is working with a small group of artists and works their butt off for them. Which one would you choose? 😉
Company A is charging you each month for representing you and further money anytime you are pitching a song to an opportunity ... Company B only makes money when they get a placement for you. Which one would work harder to get your music into a movie, TV show or commercial?
To me, the Music Gateway Sync Agency looks like a good place to go. The guys there are great and you can also ask for feedback on your songs. I have good experiences with them. If it´s about ambient music, it would not hurt to search for the companys where everybody goes, that needs that kind of music. Sadly I don´t know, which ones are the big dogs in that field. Maybe check out some of the composers that are getting a lot of placements in that area and look who is representing them.
I hope, that helps a little. 🙂
Wish you much success!