Moving from Sashido to self hosting?

I’m not sure you’ll find a free 1-on-1 tutor for your project here, but you could just document your learning process and post any issues you encounter in the respective forums (Parse Community Forum, StackOverflow, ServerFault, etc) as you go along and then share the document with the Parse Community.

There are a lot of Parse Server deployment and performance optimization guides out there, so you may want to start with a search, for example: https://community.parseplatform.org/t/share-your-performance-tips