OURtorah, the historical and grammatical answer to your original question is that traditionally, Ashkenazim have pronounced the ? as “s” while Sefardim have pronounced it as “t”. When the Zionists (Ashkenazim) took over E”Y, they spoke Hebrew with a Sefardi accent. The Modern Orthodox in chu”l, as a show of kinship with the Zionists in E”Y, adopted this accent, despite it not being in accordance with their tradition.
The answer to your underlying question, though, is more subtle and complex.
I can only try to give you chizuk and tell you to stay strong in your commitment to grow.
I can’t tell you which external manifestations of your new association to keep, and which to hold off on. What I can advise you is to hold strong to the ikkarim. I can only imagine how difficult it is for you to perform kubyd av v’em properly, for example. Hopefully, though, if you stay strong, they will see your sincerity and support you.
Hatzlocha. I’m davening for you.