Mortality rate will be quite low
Why? We did get full court press around the idea that Omicron was "mild" after the initial panic, but there was clearly no data to back this up. The typical way from the first cough to the mortuary is about 20 days. There are two obvious effects that would make a new variant appear more mild at first: If a lot of people who would have shrugged off an infection in earlier versions now get mild symptoms you change the denominator. Yes, a smaller ratio of people get severe illness, but the overall number of people who get severely ill or die could still be larger compared to earlier variants.
Two, the people who spread the virus over the whole population are usually not the most vulnerable and only a few iterations after the first outbreak will you see a large number of vulnerable people get into contact with the virus.

They did the exact same bullshit when Delta broke.