Like the OP said, I agree that leaving AP to fly the procedure is a hit and miss and I wouldn’t want to trust that especially with complicated procedures.
If using LN there is an option to include all waypoints in the STAR/SID in the export of the pln to MSFS. Then all the waypoints will be in the flight plan. It’s basically flying the procedure but by following each waypoint.
In my case, I just manually fly such procedures. It gives me full control to adhere to speed/altitude restrictions and not just let my AP decide for me. Personally I find manual flying the departures and arrivals the most enjoyable. And if it’s messed up, it’s on me.