Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4862208.
Remix of this cup holder and this Miata phone holder from GrabCad: https://grabcad.com/library/na-mazda-miata-cup-holder-cell-phone-mod-1
I don't have the OEM ashtray that the GrabCad phone holder was made for, so I remixed these two together to use the clips for the cupholder design to secure the phone holder.
Designed for a Pixel 4 XL with this Spigen case: https://www.amazon.com/gp/product/B07TDSTZXL/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=poptartingcom-20&creative=9325&linkCode=as2&creativeASIN=B07TDSTZXL&linkId=ab14754eee2866297960ee07586a4e9e (affiliate link) but I included the STEP file so you can modify it to fit whatever phone you have. The Pixel 4 XL with case is approximately 80mm x 165mm.
The holder can be rotated so the charging port is at the front or the back: just move the two clips to the other set of holes.