Why so many deaths when we have better treatments

[Sunnydaysarethebestdays]

Genuine question - I don’t understand Why are we seeing so many deaths in this wave when we are supposed to have better treatments now than we did back in March time?

The most simple answer is that we have many deaths because we have very many cases. Only about 0.5 % infected (or even possibly less) are dying now, it was about 1% in spring. However 0.5 % of a large number is still a large number.
And there are still a lot of people with underlying health conditions who are not vaccinated yet.