i'm sure that you have gotten lots of good ideas from here. Possibly the same as mine: i know how she feels. My first machine was a new singer my spouse bought for me at the Navy Exchange. I didn't like it, it seemed like i was always fussing with it. I found a used demo machine at a Bernina dealership, bought the machine in 1980, we still use it today and i only had it serviced 4x. Each time after it made a wedding dress and bridesmaids dresses. It it okay to go used, just do it with a good machine that has been serviced.
Your wife is blessed to have a spouse who wants her to have a hobby that brings her joy. I'm sure that you will find a way.