I've had two Garmin Edges. A Edge 500 I got in 2009 or 2010, that worked trouble free and was still working very well when it was replaced by a Edge 530 in mid 2020. And the Edge 530 is working very well today.

You seem to be saying you have issues with sensors being recognized when you start up. Are you ensuring that all your sensors are woken up before you start the timer or recording of your rides? Most sensors will pair even during the ride, but for some reason if my Di2 isn't woke and connected prior to pushing the timer, then it won't connect until I stop the timer and sometimes I have to save or cancel the activity and start a new one. It's seldom a issue, so I haven't looked for a solution. Other than I make it a habit to activate Di2 and all my sensors just before I power up or wake up my Edge 530.

As for not wanting anything fancy. Realize that you don't have to use the fancy features. But buying a brand that is a decently priced device that allows for quality assurance will keep you from having to hope that the cheap device you get will not be one of the bad devices that slipped through the poor quality controls the cheap brand had to use to keep their prices low.

Even buying a $80 device every other year will have been the same or more than I've spent on my two moderately priced Garmin's.