ubiq,
you are also offering a confused picture: mass shootings call a lot of attention and understandingly horrify people, but most murders in USA are not in mass shootings. There is a definite increase in the last 10 years, but it is still median number is 40 people per year (out of 15-20 thousand murders per year). These numbers are from Statista. Looked up some partisan anti-gun source and their numbers are slightyl higher: 100 people per year are killed in mass murders. Wiki listing seem to better fit the first source.
So, if you care, murderes in 2020 increased dramatically – from 15 to 20K, highest percentage increase in 100+ years.