I added a memory foam topper and it has helped immensely.
I didn’t really have back pain, just every morning it felt like I had slept on the road.
Just to revisit, the mattress had next to nothing to do with it. Funny how when my back starts feeling better, that very same mattress is perfectly fine and comfortable. I have modified my routine basically eliminating squats/deads/bent rows unfortunately. I haven’t had an episode since, but I still get pain sensations now and again. Very mild and transient. Just enough of a reminder to stay vigilant. Im stuck with leg presses and ham curls for now, as the instability inherent in single leg work like lunges etc will cause the pain to flare up again. Front squats not so great either. Im going to try light dumbell or goblet squats tonight to see how they feel.