I am confused - I have found this answer on Quora website Moreso is very well an English word. However, while it is not a favorite word with American users, it is, indeed, a word currently used by the British. Actually, “moreso” is a transitional term or adverb used to link sentences to sentences or paragraphs to paragraphs in order to further an argument on the positive side. In fact, moreso is a variant or synonym of moreover, furthermore, and additionally. Whereas “moreso” is not listed in the Merriam-Webster Dictionary, it is, nonetheless, listed as a genuine word in the Oxford English Dictionary. Actually, I have used “moreso” on many occasions when it is appropriate to do so. However, every time I do so, the spell-check mechanism comes on to indicate that “moreso” is not an accepted term. Yet, I continue to use it in that I am cognizant of the fact that “moreso” is a variant of “moreover.”

Not really interchangable. Very simular meanings. Its actually really difficult. More so and even more are interchangable. You cana even say "even more so" "Moreover is almost like a bullet point mark. I want the job done to the highest degree Moreover, I want it done fast." Frank sanatras MyWay is the only place i can remember hearing "more than this" https://youtu.be/qQzdAsjWGPg