Paul firmly believed in the resurrection of Jesus too of course, after the brain-fart he suffered on the road to Damascus, the words spoken by the "voice" he heard not heard by anyone else of course.
The reason he does not mention anything else is because as he exhorts in Galations, that is all he is commissioned to preach, in two words Christ-Resurrected, if he offers his own opinion on things he is clear to show that is what it is, unlike the GB of the WT today, he never pretends to speak for God or Christ.
Perhaps the real reason he doesn't mention the miracles and other fantastical stories is that those fictional myths , which make up most of the Gospels and much of Acts had not yet been invented and written.