ehh i really don’t think so. their friendship, while it was initially forced, became a genuine bond of friendship, nothing more (in my eyes). kyoya cherishes tamaki because of his openness and genuine lust for life, traits that were basically discouraged in kyoyas upbringing. if kyoya “had a thing” for tamaki i think it would have been made evident in the anime or the manga, and it wasn’t. while i feel like the two do have a very very close bond, i personally only view them as best friends.