As you guys mention the "pitfall" of 2p Harmonies (spending much effort on blocking rather than enjoying your own build), I am reminded of my experience with competetitive 2p Carcassone (base game). I tried it a few times but ultimately hated it while I enjoy the 3p, 4p variant a lot (mostly with friends).
I was wondering why I love the 2p Harmonies so much compared to 2p Carcasonne and I think it's because Harmonies is still way more strategic than tactical compared to Carcasonne, and blocking is only one aspect in 2p Harmonies while blocking is kind of the main game in 2p Carcasonne. Harmonies is also shorter and more "crunchy" while 2p Carcasonne has many turns and more randomness. I think I hated that your opponent constantly gets in your way (which I also always hate in Ticket to Ride) while in Harmonies you have some influence on your opponents options but at least your board is safe from your opponent and your plans can often work out even if your opponent tries to block you.
I was wondering why I love the 2p Harmonies so much compared to 2p Carcasonne and I think it's because Harmonies is still way more strategic than tactical compared to Carcasonne, and blocking is only one aspect in 2p Harmonies while blocking is kind of the main game in 2p Carcasonne. Harmonies is also shorter and more "crunchy" while 2p Carcasonne has many turns and more randomness. I think I hated that your opponent constantly gets in your way (which I also always hate in Ticket to Ride) while in Harmonies you have some influence on your opponents options but at least your board is safe from your opponent and your plans can often work out even if your opponent tries to block you.