Well it depends on how you want to attach your phone to the mount, but if you want to go the garmin mount route, something like this: https://www.amazon.co.uk/Garmin-010-11251-15-Out-Front-Mount-Computers/dp/B0096855IO/ref=sr_1_4?dchild=1&keywords=garmin+mount&qid=1597665425&sr=8-4
There are a few different ones (I think this is an official garmin one) but you won't go wrong with this style since you screw it on tight and then just leave it.
Just buy the clamp on version.
https://www.amazon.com/dp/B0096855IO/ref=cm_sw_r_cp_api_i_P2BA5XS23ZCHV0VSCRFK
Or one of its knock offs. https://www.amazon.com/dp/B07PWRVRKY/ref=cm_sw_r_cp_api_i_J5RRW9638T9SKVEKHQ0H?psc=1