How to write off a portion of your rent for DoorDash?

I have a spare bedroom in the apartment I rent and it's about 13% of the entire apartment. My desk, computer, etc are in there. I am finding that I am always in here researching about DoorDash, Postmates, Lyft, etc.

 

It seems there are 2 parts to this, regularly and exclusively. I spend 15-20 hours a week in here thus I would say I am in here regularly. 

 

However, when it comes to exclusivity the IRS says I have to regularly meet with clients here/regular place of business. In this business - I don't meet with clients at my home. Also, my vehicle would be considered my regular place of business. I am at a loss when it comes to this. 

 

I don't go in the office and watch movies - I am researching constantly about ways to improve/save money etc. It's surprising I haven't been able to find the answer to this. 

 

If I started an Instagram page for my DoorDash stuff and created post,etc. in here I could that being closely aligned, but at the end of the day how could I PROVE that I made them here vs in the living room or at starbucks?