Himari is certainly a real piece of work. If you think that the least fair character winning by any means necessary is what should happen, that sounds like a you problem.Bro she's the realest one out of all of them, certainly is the most character. You seem to prefer the wet nothingburger over the actual character. Also Himari and Tenichi have chemistry, Honoka and Tenichi are just highschool crushes that will be broken up with in 2 months. Blue Box literally did this plotline with the manager girl and best friend guy, and correctly portrayed it as the tragedy it is.
Also yea, she does some stuff. So? Tenichi was clearly very broken up by them actually parting, in equal measure to Himari. For him to immediately go to Honoka without reservation or second thought is just bad writing. It's boring, it feels hollow, people are left feeling empty rather than having bittersweet understanding, and it sucks.
Yes, Himari gives me Ayame and Hina vibes. All three characters are selfish prats who don't genuinely care what their crushes want, and act without ethics. Not into stories that reward characters like this.