This is history in the making. Huge props to Oregon legislators for spearheading the change. Soon we’ll see official psychedelic therapy centers operating in the open and this is hands down one of the best things for the society.
As somebody who did it several times in multiple companies, it's not as hard as it looks. Usually you don't want to replicate your complete frontend experience, only the user facing part (and admin panel/etc can be a lot of product). Also things like notifications, emails, etc are all usually dispatched from your backend.
So in a lot of cases having just 1 engineer per each mobile platform would be enough. And if you spend say 3 years building backend + web frontent, it would take about 6 months for each to replicate user facing experience on mobile. With current average global quality engineering cost of 70k/year, this means it only costs about $70k total to ship both mobile apps.
There are many ways to do it less efficiently, but this is my personal experience (as a CEO, EM and also iOS engineer in different setups) and it's really achievable.