I’m fortunate in that Merlin had always worked for me on my FP3+ and now my FP6.
Having said that, I’ve just started using BirdNet Live for sound ID, which comes from other developers at the same organisations (Cornell Lab of Ornithology and Chemnitz University of Technology).
May be worth trying if you can’t get Merlin to work.
I’ve not yet had a chance to compare apps in the field, but running a few recordings through both BirdNet Live and Merlin there appears to be close correspondence in the results. None of these sort of apps are perfect though, as your example shows!
A couple of things I like about BirdNet Live is that it gives a confidence value against each ID, like in the original BirdNet app, but performs live ID offline, like Merlin but unlike the original BirdNet.