It's called slow burn for a reason
Slow Burn 40 chapters bffr
Especially cause in slow burns you at least see the Progression. Here is none
40 chapters lol I've read others that were a lot slower. And if it's so easy for someone to accept dating someone way younger than them (and outside a work relationship) then this would be such a cliché manhwa like all the other stories with charas who have hooked up in the first few chapters. Maybe this isn't the story for you. Or maybe you'd prefer the novel since they go more in-depth with pov and you can binge read it cos it's already finished.
When are they finally be closer I feel like whenever I check up on this they are still on the same Level. It's so boring