Have you ever said something like this?
A: How was your weekend?
B: It was fine. I could enjoy a relaxing time.
A lot of non-native English speakers use “could” when they talk about things they did, but it sounds very strange in English. "Could" is used with “have” to talk about things that did not happen, and it's common to add a conditional "if" statement.
I could have enjoyed the meal if it wasn’t so spicy!
Could have may also be used when you aren’t sure if something has happened.
A: Has Joe already arrived at the office?
B: I actually just arrived, so I’m not sure. He could have.
"Could" is usually used to show possibility. It is also used for things that did not happen.
If you want to add impact to actions, simply use “really”, “a lot”, or other intensifiers.
A: How was your weekend?
B: It was great. I really enjoyed it. I just relaxed at home.