Bamboobamboo seems to stick
I have been through this struggle. I have the Stokke tray for the Tripp trapp and have put on this cover - https://catchyandcrew.co.uk/collections/stokke-tripp-trapp-high-chair-accessories/products/suction-solver-2-pack
Sounds silly but follow the instructions on how to attach it.
I have the Amazon tray instead and everything sticks
I have a dupe for the tray but I’ve got the brand “panda ear” from Amazon which have been great, all of my others don’t stick xx