The Rise of Phoenixes (2018): It's a C-Drama and the ML does exactly what you ask for.
*I saw you dropped it, but I still write it down because others can like it instead; I personally loved it.
Healer (2014): K-drama (Once again, I saw you have this already in your list, so it's not helpful for you, but it can be for others)
Mr. & Mrs. Chen (2023): It's a C-Drama. They both pretend to be a little "dumb" about things, because they need to hide they're both spies