Change zoom toggle to hold-to-zoom?

Hi,
RMB by default toggles into zoom mode. Is it possible to change to hold-to-zoom?
I learned that z and RMB are `weapalt`, so for the knife it's actually not zoom; but for all the weapons I have at the beginning it is.
Internet search also taught me that `+zoom` is something else: seems to be scoped zoom, which then also "works" on non-scoped weapons. That works hold-to-zoom but isn't the feature I want.
Any ideas?
thanks

necroing, because i have the same issue

Please add it as an option not a straight change, I'm disabled that would be uncomfortable at best for me