This is what I am using. Probably won’t get the official one as this works pretty well. Just use and adhesive strip to attach the hub to the base.
USB C HUB 4K 60Hz, Dockteck USB-C... https://www.amazon.com/dp/B08SM393WB?ref=ppx_pop_mob_ap_share
USB C 90 Degree Adapter Up Down... https://www.amazon.com/dp/B08CDGHQWF?ref=ppx_pop_mob_ap_share
Stand Base for Valve Steam Deck... https://www.amazon.com/dp/B09TW292LK?ref=ppx_pop_mob_ap_share
I've been perfectly happy with this dongle that I purchased in May when I got my deck. It hasn't given me any issues and supports HDMI 2.0. I also use this plastic stand with the dongle attached to the back with 3m double sided adhesive tape. Combined with a 90 degree adapter it looks like a seamless dock.