I found this post by Butler Lexus in Macon, GA to be very helpful. Especially the bold options, No# 1 remote start option via key fob and No#5 turn of key fob, these both work on my new GX 550!
https://www.butlerlexus.com/blog/2023/march/21/lexus-key-fob-hacks-secret-fob-tips-lexus-macon.htm...