One option is to use the search function within the Messages app and include specific keywords or phrases that may have been mentioned in the messages you're looking for. This can help narrow down the search results to messages sent or received around the date you're interested in.
Another option is to manually scroll through your message history to find messages from the desired date or date range. While this method may be more time-consuming, it can be effective if you have a general idea of when the messages were exchanged.
If neither of these methods yield the results you're looking for, you may want to consider reaching out to Official Apple Support for further assistance. They may be able to provide additional insights or suggestions for searching messages by date or date range, or they may be able to escalate the issue for further investigation.