Halo MCC shouldn’t have MTX added to it, period. You already have The Exchange where you can get previous unlockables. You can already retroactively go through different Seasonal Passes or however they are called.
Don’t add MTX.
Adding my opinion to the collective so that hopefully it helps send the message that we, the players, do not want this. The monetization and customization of Infinite is already bad as it is. If you need funds, continue to update Infinite with things worth buying.