
Imperial Russia was actual chill with the US. But was not so friendly with the British empire.
It knew it couldn’t keep Alaska so may as well sell it to the Yankees before the British take it by force.
Lichtenstein also offered to buy it but that deal didn’t go through.
I think at the time they didn’t believe a republic could really work for a large expansive country and would just use it for smaller city states. Hence why Florence and Venice and San Marino were Republics but then Naples and Sicily were monarchies.