I got this to work by doing the following (the recommended code above used Loved instead of Love, which is the correct variable):
Virtual1: $If(<Love>="L",1,0)
Virtual2: $Sum(<Virtual1>,<Album Artist>)
And then configure an auto-playlist with this criterion:
<Virtual2> match RegEx [5-9]\d*|\d{2,}
I had to use RegEx because the dropdown in Musicbee didn't give me the option to use "Greater than". Which seems kind of stupid, so I was forced to use the RegEx and ChatGPT to help me with that nonsense (it looks like Greek to me, but that code says anything greater than 4). So now I have it working. If I heart/love more than 4 songs of an Album Artist, it will appear in my auto playlist. Awesome!