Yup, so it is possible to skip Blue gear. Of course you need to have some research and runestones leveled first! I made it to Dragon Spirit Floor 35 with green gear!
I’ll forewarn that you can’t miss the guardian on Floor 34…if you go the wrong way and fight you may not have the health to beat it.
I’ve gone from Green to Purple gear twice and plan on repeating this with all my farms. Then they unlock 41 and from there I can plunder from floor 21 everytime and fill my bags.
Once I have sufficient coins I buy and level my runestones before attempting Floor 55. It’s easy if you stage it out. Especially if you are doing all of your farms at the same time.
Research and Runestones Used to unlock Floor 35: