1) Wrong. It does help my original statement: "In this context, vaccines that do not provide sterilizing immunity (and therefore continue to permit transmission) will lead to the buildup of large standing populations of virus [47], greatly increasing the risk of immune escape." ... "Thus, our findings speak to the need for both public health and biomedical intervention strategies targeting SARS-CoV-2 to be designed to account for the risk of rapid evolutionary response to biomedical interventions."

2)Wrong again: "In the presence of mixed sera from multiple previously infected and/or vaccinated individuals these infections would create the appropriate conditions both for genetic recombination to occur, and for selection to rapidly sort multiple recombination-generated combinations of input immune evasion, cell entry and replication impacting mutations."

My original point is that people that made use of covid mrna therapy can be the source of new versions of the virus (because the therapy doesn't prevent infection nor spreading of the virus).

While it's true that the second study talks about mutations in both vaccinated and unvaccinated hosts, the first is clearly looking into the spike protein based therapy:

"The spike protein receptor-binding domain (RBD) of SARS-CoV-2 is the molecular target for many vaccines and antibody-based prophylactics aimed at bringing COVID-19 under control. Such a narrow molecular focus raises the specter of viral immune evasion as a potential failure mode for these biomedical interventions."