Yeah, generally, not disrupting the substrate is a good thing. I prefer to leave my substrate alone if everything is good. But I suspect you have a lot of trapped organics there, based on pics. I am willing to be wrong. Since you're having issues, then you have to take otherwise disruptive steps. Also, a good substrate cleaning is not something you do weekly. Once done and the problem is fixed, you may not need to do it for another year. After this one-time substrate clean up, then you can turn your attention on trimming iffy leaves, water changes, adding oxygen and surface agitation, adding shredders (shrimps and snails) etc. to manage organics. Ultimately, there is nothing like water changes - big, frequent ones to get the problem under control.
As for the good advice over at UKAPS, I don't disagree that mulm in the substrate gets processed into plant food eventually. In lower tech tanks, that's how it works. If you've noticed some of the most successful high tech tanks, like Tom's, go thru an awful lot of uprooting, rearranging, moving, scaping and general mayhem. Do you see his plants suffer? I do a lot of this myself and my plants are fine. I do more now with confidence than before. The plants could always handle the disruption if you keep it to a section of the tank. I was the one lacking confidence and skill in measured and calculated disruption. Over the weekend, two-thirds of my 6-foot long tank was plant less. I was moving things around. Fully re-planted now. Tank did not skip a beat.
I am not convinced that Clado is SOLELY due to organics. It could be partially caused by it. I had Clado a while back when I had very little organics and did water changes like a mad man. As my general husbandry got better, the algae went away. In the meantime, use a spare comb from your bathroom to comb out the clado. Worked pretty well for me.