You know what would be a cute au?
Daycare owner Yuuri and single dad Viktor.
Viktor moves to Japan with his son Yuri after a divorce. He barely speaks the language, has zero friends to rely on and the only one that seems to care is the adorable man that runs the daycare he takes his son to. The guy even offers to teach him japanese!
They soon become friends and Yuuri even invites them over for dinner sometimes since he knows Viktor is struggling with money. Every now and then he would even watch little Yuri if Viktor had to work overtime.
In return Viktor cooks Yuuri delicious Russian food.
They fall in love of course and are just so happy and domestic and just the cutest little family.