In March of 2020 we were pretty sure that at most 5% of Covid transmissions were through touched surfaces (fomites). Currently we're sure that at most .01% of Covid transmissions are through surfaces and still haven't found clear evidence of it ever actually having happened so literally 0% still can't be ruled out. But upper respiratory tract infections like the flu do actually spread through fomites pretty easily so we've defaulted to the flu playbook for many public health measures.

There are a lot of diseases out there that are transferred on surfaces however. Not everything is about covid

They have known this since april 2020, it was a German scientist that first tested this I believe.