We get you don't like Raymarine.
Your experience seems to be an extreme....juse pointing that out...could care less what you buy.
There is a story like yours for every manufacturer...I worked and installed for years at a marine electronics shop, have been teaching boating for decades, delivered boats and met hundreds of boaters every year when I towed them....heard complaints and praises across the board on just about everything marine.
Went to this video on controlling the autopilot from the mfd....seems pretty simple..... yes Garmin is pretty savy abut simplicity...but I don't see where the raymarine software was written by Ralph Nader...
https://youtu.be/aEhBdIO7jfY