Dispenationalism is a teaching tool that began in the Nineteenth Century as a protest against Protestantism, as it were. Your toolset has a problem in its lack of apostolic provenance.
If the tool works, why reject it as not old enough for your comfort? It is a tool, not some rite set in stone. It does do what it is intended fro, even if some refuse to use it to aid in their understanding. Post verse after verse from Old Testament covenant teaching to address the New Covenant is an error easily remedied by use of the useful tools. Posting three passages addressing previous covenant aspects as if they are covering the New Covenant is demolished by just looking at Paul’s Epistle to the Romans ... by the law of sin and death no man shall be saved, for it is by Faith you are saved in the New Covenant established by the shedding of Christ’s blood AT THE CROSS, not on a catholic altar.