Right now I know of at least half a dozen products that are marketed as having E2E encryption but do not actually implement this (no, I'm not going to out them. See second to last paragraph as to when to be wary). In part because executives, marketers and salespeople don't know what it means. And in part because when explained what it means they will insist on their own definition/interpretation and demand the product is marketed as E2E.
It is also important to note that quite often you are not dealing only with the company that makes a product, but the regulatory bodies that can pressure companies into complying with their wishes.
As for Zoom, I don't understand why people trust them or still use their product if they are at all concerned about security. It makes very little sense.