You apply the word 'let' too loosely. Where is your link backing up your claimed number and the negligence you infer?
Trump let the Covid response be politicized, encouraged it, resulting in 100's of thousands of unnecessary Covid deaths.
That politicization, 'downplaying', carried over into the vaxxes which Trump remained silent about for a full year, resulting in more unnecessary Covid deaths, mostly among his supporters.
Trump 'let' his dumb ass supporters believe the election was stolen, misled them into believing that, and then used that misguided belief to incite them to treasonous insurrection with the intent of keeping himself in power.