This is so simple, and people are trying to make it hard. You have an action on your turn. You take your action. You can move before and/or after. If you have a bonus action, like the rogue, you can take your action, then your bonus action or you can do your bonus action and then your regular action. You can move as much or as little as you want between your action and bonus action, but not during your actions. Done. That's the rule. There's an exception, but that's irrelevant.
If you don't have a bonus action, but an action you perform grants you a bonus action, then you take that bonus action after your action. Because you don't have a bonus action before your action, obviously.
You can't dash as a bonus action first and then cast Expeditious Retreat later. You can't order your Unseen Servant to bring you the material components as a bonus action so you can then cast Unseen Servant. You have to do the thing that gives you the the bonus action before you get the bonus action. How is that not common sense?
Of course now we are dealing with the fact that people don't like to be wrong. Once a decision is made people (including me) will stick with it. They'll start making excuses and rationalizations. And the more they do this, the more invested they are in making sure they are right. The more they will refuse to agree that they were wrong. It's embarrassing. "How could I be so wrong, for so long? No. I wasn't wrong. I couldn't have made that big of a mistake. I didn't waste hours of my time and dozen of post defending something that was incorrect."
Of course some of us here has done just that. It may be the side you are on or the other side. Each side of course thinks it's the other side. But please consider. Maybe you're wrong.