We sent them over 200 pages of communication like chats and call histories last month. Now they are asking for travel history after marriage but we couldn't due to Covid restrictions. Not sure what to do now.It is a bad sign. You need to prepare as comprehensive a response as possible. If you've not yet ordered GCMS notes, possibly too late.
Read the letter very carefully to see if there are any specific clues as to which evidence they are most looking for, like dates of interest. From what you've mentioned, ongoing communications and contact and support before and after marriage unless there are dates referred to, but obviously that's a bit generic.