More deadly because while it may not make people any sicker than the original SARS-CoV-2 (the same percentages without symptoms, with symptoms, and deaths) it will spread to more people so there will be a greater number in each group, meaning a greater number will die.

The weak spot in the US response now is the available number of vaccine doses, but the numbers that must also be considered the the number of doses sent around the world. Rich countries hogging the supply leave poorer countries much more vulnerable and allow for the further mutation of the gene that will eventually come back and bite everyone in the ass. There used to be a formula for the number of doses sent to poorer countries outside the US, but of course Trump trashed it along with the science committee that looked into pandemic issues. All of that has to be rebuilt quickly.