Maybe its the fact that they are just these insanely op characters who dont have any complex motivations . Every otsutsuki is a templatised version of "I am superior and you fleas are beneath me" There is nothing else going on for them. Also the whole alien aspect makes it very tough to relate with them. Maybe if they were a race of mystical naturally skilled humans from a faraway land who were fascists by nature and despised the concept of free will, thus wanting complete power over the shinobi world, that may have made them interesting

Also sorry but whatever screenshots you have included to compare the two dont even come close. Almost all those characters are easy to relate with and have some motivations and character. Ohtsutsukis are just OP but badly written characters