Hi and welcome to the community.
I am just beginning the project of opening my BT5245 overhead TV cabinet space. There is a tremendous amount of unused space up there. I will be doing the carpentry over the winter.
You can get a small kid up there. The extra storage will be well worth the effort as well.
Here is a link to another posting that has already done the project:
Hey-lam, new 2020 bt cruiser 5210
He has done a tremendous amount of work on his 5210 and you will have to go to page 3 of the thread to see a picture and description of his TV cabinet project.
The pink fiberglass will have to come out as any floating exposed fibers are a health hazard. I am investigating some alternatives for noise deadening and minimize heat penetration.
I would be interested in your approach as well.