Tips to progress from 30-35 m to 40m

Hi fellow freedivers!

Currently a Wave 3 diver looking to progress to greater depths.

I remember feeling completely out of breath/compressed chest feeling/struggling to equalise (Frenzel) at 34-35m (during Wave 3 course). (Haven’t attempted yet) but 35m+ feels out of reach…

Any thoughts/suggestions on training to enable depth progression?

Thank you! 🙏