So uh, is there any bl works that realizing aka's principle omega is the ruler and top cha...

Yes Unromantic!

Omg how can i forget this oneeee thank u for reminding mee!!! (≧▽≦)

Well, what about these:

Very similar premise but no fiance trope or rich people- https://www.mangago.me/read-manga/seku_tsuga/

Same mindset- https://www.mangago.me/read-manga/unmei_no_kisu_wa_oazuke/

Omega is in charge-
https://www.mangago.me/read-manga/the_omega_takes_a_husband/

https://www.mangago.me/read-manga/a_tough_alpha_wants_to_be_loved_cornered_by_a_young_omega/

They've got spirit-
https://www.mangago.me/read-manga/katsubou_animajemera/

https://www.mangago.me/read-manga/megumi_and_tsugumi/

THANK U SO MUCH for your effort listing these amazing manga (ಡ  ʖ ಡ)人 kinda funny i alr read some of them and even rate 5 star XD gotta check those new titles yay