This is the best writing advice I ever received:

"The first rule of style is to have something to say. The second rule of style is to control yourself when, by chance, you have two things to say; say first one, then the other, not both at the same time."

It's a quote by George Polya.

The paragraphs you have written don't seem unprofessional to me.

The best way to improve the "flow" of ideas when you write is to have a clear idea of where one idea ends and the other starts.

For longer pieces of writing, consider intentionally "signposting", by saying meta things like "now that I have explained X, I can set out why Y is so interesting".