Umi is not a villain.
He praised Kazuya was the work he did with fundraising. Told him that he must be smart for figuring it out so quickly. Put his picture and twitter handle out there for his 270k followers. I expect Kazuya to get some business helping other people get funding for their films. This will be an important part of Kazuya's growth as a character. Part of his anxiety was seeing his future in running the family liquor store. Getting into movie production was be the cure for that.
When people figure out that he can set, and execute, film budgets, scout locations, manage film sets, chase away cicadas, etc, he'll get more work, and more lucrative work. Not anyone can do this, and most actors/actresses/directors are terrible with money. Film studios NEED people like Kazuya.
Why'd he tell Kazuya "I don't not like him"? He's nudging the relationship along. I think we all agree that it is time to fish or cut bait, and throwing this out, once shared between the two, brought that up. Nothing wrong with that. If Chizuru is uncomfortable with dealing with her feelings towards Kazuya, that's causing him pain. She knows how he feels, and the longer she tries to maintain the status quo, the worse it is for him.
People who view Umi as a villain are projecting their preconceptions on him. This chapter shows that.
Unless of course the gift Umi gave Chizuru was something romantic like a diamond ring. Then I'm an idiot.