You must do your best to pronounce the letters correctly, and in sha Allah
your prayers are valid. This can only be done by practicing it with a good
teacher.

I want to perform my Salah with gud tajweed but I stress on letters thinking I didn’t pronounce them well and might be if I leave the correct pronunciation on purpose Allah won’t accept my Salah. Shaikh is this true if u mispronounced something like “kaaf or ayn or ha” I mean u read them as small kaaf and alif and small ha.plz help