I bought some of these because of the same issue.

Car Seat Gap Filler Organizer, 2... https://www.amazon.com/dp/B096VFKPLG?ref=ppx_pop_mob_ap_share

I bought this from Amazon and it works fine for my keys, phone, and sunglasses. Sometimes I put a drink in there. The package comes with two but I only use one on my passenger side

(https://www.amazon.com/Organizer-Multifunctional-Console-Storage-Sunglasses/dp/B096VFKPLG/ref=mp_s_a_1_15_sspa?keywords=car+seat+gap+filler&qid=1687314724&sr=8-15-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9zZWFyY2hfYXRmX25leHQ&psc=1)