What do you do about accommodations on airlines? Specifically low cost ones that limit baggage?

Hi everyone, I'm having kind of a hard time dealing with a very low cost airline (spirit).

I have explained to them that I need to bring some sensory items with me that help, including a therapy lamp some stimming items sensory clothing, and activities that keep me occupied because flying is a very stressful experience for me.

They told me that I can bring an extra bag without paying if it's examined by the gate agent .

Basically, even though they consider these items, medically necessary, it needs to be a "medical bag" with only the items that are medically necessary, and no personal items.

I explained to them multiple times that a gate agent is not going to be able to distinguish between medically, necessary items and personal items for autism , but I still need these items for my condition.

It's also very stressful for me to think about having to go to the airport and then additionally have my stuff scrutinized by a gate agent who might just end up charging me. They're refusing to let me have a normal bag added.

Should I just pay for the bag?