You can use a mount like this which can be put between your center console and the passenger seat. Very adaptable and can be taken out when you wish to leave no signs of the install. You will want to pair with an external antenna though for best signal. HTs don't receive well in a vehicle.

https://www.lidoradio.com/collections/collection-of-mounts-for-all-amateur-radio-hts/products/lm-wedge-ext-wedgemount-with-mic-holder-for-all-hts

Take this and pair with an adapter that you then connect to an external antenna with a mag mount or someother NMO mount, and you can have an install that works but can be temporary and removed in 5-10 minutes.

https://smile.amazon.com/gp/product/B08BNN4RV1/ref=ppx_yo_dt_b_asin_title_o08_s00?ie=UTF8&psc=1

https://smile.amazon.com/gp/product/B0842BB2R9/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1