dfk41 Don’t think so much about identifiable flavours, think more if there is any flavour intensity (of whatever, or just muddled), what would be your liking score for the last brew (this is more helpful)?
Somehow at the coarser grind, the brew has not sped up any (could just be down to larger output), you might be able to go coarser?. 20g doses sound good if you’re not getting any intensity, maybe even try 21g as long as you’re not in danger of overflowing the basket.
Be aware, that if you grind too fine, you may not get smokey, sickly, over-extraction…you may just get muddled, tangy under-extracted brews. So I’d carry on with grind adjustments in one direction to force a malfunction and confirm any fault (in the technical sense, other than the coffee itself not meeting expectation).