Any chance you sit your pedalboard on top of an amp instead of the floor? A long shot, but I've seen it happen. The pedal that amplifies sound is sitting on top of the noisy part of the amp, I think the transformer usually, Agedhorse may smack my hand on that statement, so I'll just go with "the noisy part". And then, as previously mentioned, try a battery to rule out power supply issues. I picked up a couple of these so I could try battery power without cracking open the pedal. Lazy or practical?
https://www.amazon.com/AUGIOTH-Battery-Converter-Center-Negative/dp/B091FFHZ71/ref=sr_1_2?crid=3Q6KZ9CU2SBJ3&keywords=9v+battery+center+negative&qid=1643307661&sprefix=9v+batter+center+negative,aps,44&sr=8-2&th=1
Side note: I wonder how safe it is to run a non-battery compatible pedal w/ these things in a live situation. Lol
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