My impression is that many or most of the frequent contributors to this forum are aged approximately 50 to 85. While those with a lot of experience traveling can share better wisdom on average than me, the older somebody is, the more hypercautions they need to be about catching diseases - a disease that wouldn't be serious for me could be sever or fatal to somebody 2x my age. Not that I think it is ok for me to catch coronavirus-2019 or develope coronavirus-2019 disease. I actually never caught the disease and my plan is to never get it. I actually have tickets to fly to Spain in October of this year, 2021. My best prediction is that there will never be a special day when, in terms of this pandemic, it suddenly becomes safe to visit Mexico. It will never be more safe than today to visit Mexico. January 2022 will not be safer than now. If you keep waiting for somebody to tell you it is safe to visit Mexico because the pandemic is "now over", you will never visit Mexico.
My real suggestion is, visit Mexico as soon as you are willing and able to get the time off work. Just don't drink the tap water, be careful about what water you wash the produce you buy in Mexico with, read the guidebooks carefully and pay attention to what neighborhoods the writers suggest you visit and which ones they suggest you avoid, and possibly talk to your doctor about how to avoid malaria, and gastritis caused by norovirus, rotovirus, or food poisoning, and so on. I actually had some severe gastrointestinal symptoms right here in my home town last September; the doctor at the hospital finally decided that I had a virus in my digestive tract. But I had zero problem with my respiratory tract, so I know it wasn't influenza or coronavirus-2019. As I remember, you already had ccoronavirus-2019 and you already got vaccinated, so you should be well protected against further coronavirus-2019 infection, plus you are not going to eat too close to strangers, so I think your risk of getting the disease again is negligible. I would be interested in hearing how your trip worked out.
Edit: regarding crime: crime-stastics cover an entire city, state, or country. If you read the statistics about other countriex and cities, in Mexico, Europe, and everywhere, and you worry too much, you would never travel more than a few miles from home. The statistic don't accurately tell you whether you personally could safely stay in a hotel in a city and safely travel from your hotel to museums and monuments. I know analogies are not persuasive - The city of Detroit is known as an unsafe place, but most of the crime is in the ghetto, gang-infested residential areas. I have been to the Detroit Institute of Art with my family, and to other sites alone, in and near downtown Detroit, without a problem.