Remove your mbc and run the pressure line directly to the actuator. Easy win for safe turbo pressure until you figure it out.
Yup, good starting point, factory wastegate setting is about 10psi which won't help your power situation, but will keep the turbo safe. Also make sure the hoses from the turbo compressor to MBC to wastegate are tight and free of damage, the fact your boost levels are soaring sounds like one of the hoses popped off or the hose got damaged.