I assumed TLM and Tridentine are the same. If not my apologies. I certainly did not mean to denigrate it. I’m not honestly sure how old TLM is. You state a general misconception of about 450 years, I thought 800. When did this form of the mass start being used? There are many Liturgies that date back to the first 4 centuries, I don’t believe this is one of them. I would be happy if you could further enlighten me.
Liturgical scholars are not exactly sure when the Roman Mass came together in the form we know. We find it pretty much intact in the earliest manuscripts (from the 6th-7th centuries if I remember right). The Mass as described by St. Augustine in the 4th century shows that certain key features were already in place in Africa. And there is some evidence that it went back all the way to the earliest liturgies in Rome: particularly the absence of an epiclesis which seems to date to a time before the theology of the Holy Ghost was completely worked out.
Basically, as far as Rome goes, the traditional Mass is the only one we have solid evidence of; there are certain disputed liturgies like the Canon of Hippolytus, but they are of questionable provenance.