Here is a cradle I found on Amazon. It is not as good as the Harmony Elite cradle but it works well. Does not include the power brick. Due to the nature of the USB-C connection, there probably isn’t a dock solution like the HE.
Sinjimoru Phone Dock with USB C... https://www.amazon.com/dp/B07GQV2NXN?ref=ppx_pop_mob_ap_share
If nothing else, it might give you some idea for your 3d cradle design.
There is an app on the play store called button remapper. It let's you bind any button (including long presses) to any app/function.
I have red for Netflix, blue for prime etc.