Your take is fair first off.
Looking at the Rams prioritizing run defense, I think this DL group had a lot to do with that. Kept hearing scouts say "just pick a trait" with this group because they felt you're not gonna get those all around types that frequented the previous two years. So the Rams did that.
As to why they prioritized run defense beyond that, I go back to 2017. The moment Brock went down we lost our ability to stuff Atlanta's run game. And he was not exactly a primo run defender. In fact up until last season the Rams were mediocre at best vs the run. IMO when Staley came in and got this group playing good run defense they were ecstatic. But they still got bullied by some fronts to include Green Bay sending them home in the playoffs in large part due to that.
So after the Rams let Brock and Fox go this offseason the writing was clear IMO. Fans might not get it overall but as a guy who loves defense I certainly do. Also I think Bobby Brown was their best pick of the day. He's 20. The guy is going to push Robinson at 5T immediately and may win a starting gig.
Re: OL really the problem is what happens next offseason. But the Rams wanted speed and physicality on defense first. That's gonna be a next year problem.
This team is chasing a championship. They want it now. So they prioritized the things that help them get it now over easing next offseason in their OL room.