I'd go with Volaris as long as you have taken their bag fees in to account. I find them to be easier to deal with than Viva or Aeromexico when things go wrong. For example, I didn't have any issues getting a refund from them due to pandemic-related flight cancellations or when I recently needed to cancel a ticket shortly after booking it. They generally operate on time and run a pretty good airline. Viva is good too but can be a little more difficult to deal with. Aeromexico is usually much more expensive and not really worth it unless you have status IMO. Also there is no TUA on intra-Mexico flights and it is very easy to avoid paying on Volaris even on international flights inbound to Mexico. Let us know who you pick and how your trip goes!