Thanks for sharing your experience, as unfortunate as it was. Roth conversions are indeed tricky. As I wrote here, using them can reduce or even eliminate RMDs, but it was beyond the scope of the article to get into the details of if, when, and how to do them to avoid the very problems you mention.

In my case, I had to build an elaborate spreadsheet to assess the scenario and it's tax impacts on me over decades. The result showed that it would end up costing me more than it saves.