OK, this conversation has taken an interesting turn - and I'm pleased that Plexi has turned up because he has forgotten more knowledge than I'll ever learn...
The Origin is no DSL. It is not a high gain amp and does not work in the same way a DSL does or have the same characteristics that a DSL does; but because I've owned both and most of you have knowledge of the DSL, I will compare/explain the two - and why this leads to the problems I am having... (Then, Plexi can correct the nonsense I've written...

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The DSL and Origin both have 3 similar preamp tubes and 2 EL34 power tubes, but that's where the similarity ends - these preamp tubes and power amp tubes work very differently in the two amps.
The DSL has a lot of preamp gain and low headroom - it is easy to get drive at any volumes because the preamp tubes are doing a lot of work on the sound, and, thus you have a low headroom and pedals, such as a tubescreamer, work ok at any volume (I didn't say work well...).
The Origin has very little preamp gain and very high headroom - the amp wants the power tubes cooking before you close the headroom and get the underlying tone that would take drive pedals well. On high volume, i.e. volume and gain from the power tubes, something like a tubescreamer sounds amazing. On any volume, without the power tubes working hard, drive pedals sound poor...
The two amps are just very differently designed. The Origin has really nice cleans, and I can get to nice breakup sounds with the SGs powerful P90 - sounds great (better than I ever got the DSL to sound for bluesy tones, to my ears).
The only way to get drive pedals working well on the Origin is to crank the power tubes/Master Volume - this can be done at low volume levels with an attenuator because the power tubes would be pushed.
What amp are you playing the pedal board through?
Marshall Origin 20 combo - comes with a Celestion V30 10" speaker which sounds good.
I'm surprised that you couldn't find harmony with that Tube Screamer.
I don't think you can find the right soundspace without pushing the power tubes hard - at my pre-85db levels, even at 3w, I am not pushing the power tubes enough to get the sonic space required for a tubescreamer. Having said that, if I twiddle the knobs enough I should be able to find some decent tubescreamer sounds, you would have though - & some are decent, just not as good as the SG and the amps boost, to my ears anyway. At high volume, at a rehearsal or gig, then a TS would sound really nice (I'm pretty sure).
How does your experience compare to what you see and hear from this following video demo?
It sounds the same without pedals. But, these demos all sound much better than I can get when they add drive pedals because thye are usully on the 20w setting and around 100db.
Reading on the Marshall forums, some folks say the Origin is great with drive pedals and others say it's terrible - they are both right. It's great if the volume is up, crap if the volume is not cranked. I think this is a well known plexi style amp characteristic, but I just never owned an amp of this type to fully understand what I'd read many times over...
Are Marshall amps all about the crunch and distortion?
No. Some are, some are not. Now that Scando fella that does the amazing videos makes even the low gain Plexi amps sound amazing (the Origin is in that general style), but he cranks the power tubes to get those amazing sounds.
Can be maddening especially when you cant crank it into "the zone" due to volume restrictions
Yeah, basically that's it. But, at sub 80db levels I still get really nice blues/classic rock sounds as long as the guitar has a bit of oomph from the pickup(s). I really like the sounds I'm getting with the SG. &, the Origin's boost works great at all volumes.
My point is Early Marshall amps are not high gain
You, Sir, are correct. &, they have really high headroom too if they are anything like this Origin 20.