I've got a Mavic Pro 2 and a Spigen Tough Armor case. Works fine with the Pgytech tablet holder. It has a tension spring to hold it firmly and I'm happy with it. I rotate it so it holds it in landscape and it's good.
Under $20 on Amazon and you can find it here.
PGYTECH Pad Holder 4-10.5 inch Holder Remote Control Tablet Mount Holder for DJI Mavic 3/Mavic Air 2/Air 2S/Mavic Mini/Mini 2/Mavic 2 Tablet Holder Foldable for Drones Accessories https://www.amazon.com/dp/B085TC9RFM/ref=cm_sw_r_cp_api_i_BR4MPB56A71SX4JF04WH?_encoding=UTF8&psc=1
This is the one I use. It super compact when not in use.
Something along the lines of this would be needed https://www.amazon.com/PGYTECH-Control-Compatible-Foldable-Accessories/dp/B085TC9RFM/ref=mp_s_a_1_3?crid=39RPO06UK2W51&keywords=tablet+holder+for+dji+air+2s&qid=1638335049&sprefix=tablet+holder+for+dji%2Caps%2C86&sr=8-3
I know this says Air 2s but the Mavic 3’s standard controller and the Air 2s controller are basically the same and have the same dimensions
I bought and used this one > https://www.amazon.com/gp/product/B085TC9RFM/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
It is sturdy and definitely works, and its only $20. I got that + a 1' cable to connect my ipad to. No bad things about the mount, it fully supported my ipad in an otterbox case. That mount is actually mentioned in the video a previous person posted in your thread. It works.
I just received these two yesterday and will be using an iPad mini as well.
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https://smile.amazon.com/gp/product/B085TC9RFM/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
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https://smile.amazon.com/gp/product/B07VQGF6Y5/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1