I use one service, which has a huge amount of quality music, I often insert in my videos on YouTube or sometimes do editing videos to order. In the same videos for clients I use non-copyrighted music from inaudio service. There are a lot of genres of music there, so it's no problem to choose something you like. A symbolic value of $ 6-7 per month is not that big. You can download music, or you can contact the authors who created it and collaborate with them if you want.

Professionals in development always take care that their application is fast, there are no delays when working with the database, etc. Usually if you order development from a big company they do all the testing to give you a fully working and corrected application. Here is a great example of tip doc care web app https://owlab.group/case-studies/tip-doc-care from owlab. The application was developed for a clinic that has a lot of foreign patients, to optimize and simplify the work with them.