"Small DNA viruses may encode their own DNA repair, and some RNA viruses also share the ability to check for and repair replication errors.
However, while DNA viruses generally rely on the transcription machinery of the host cell, RNA viruses encode for their own transcription machinery."

What about intentionally encoding our cells with mRNA virus via Vaccines?  I mean...is that Not exactly what Pfizer and Moderna vaccines do??  Create mutations and variants by genetically modifying our cells?