Could I just comment as a user of both 4D and a Joomla CMS.
We use 4D for the business in the “real world” and Joomla in the “cyber world” and so far never the twain shall meet. (If it is possible to dive into Joomla’s sql and extract the relevant data to unify our slightly schizophrenic business model then that falls into the “one day” category.)
I have trouble keeping up with 4D (currently moving to get the v16 purring) never mind the pool of technologies that the web employs.
Hence the use of Joomla and a cart.
For your points 1,2,3 and 5 can be pretty vanilla in Joomla.
Point 4 - the address.
Do your users know their geolocation? In a land of “no addresses really” is that the norm? What did people do not that far back before GPS? If users know their GPS then I would imagine that it shouldn’t do too difficult (I know “The simple things are all complicated…”) to somehow incorporate that into a cart address structure with creative use of existing fields. If they don’t have their GPS to hand then a site like latlong.net could either be built in to (or referenced by) the CMS. There are extensions for Joomla which “do” GPS but I have absolutely no ken as to what they do.
Point 6 may or may not be capable of being handled in the CMS, but the name (who) and the goods (what) is pretty standard stuff, and if geolocation is the norm then surely the delivery people (who I assume are offering a service for which they are being paid?) will have their own maps on which they work - let them handle it, it’s why they are being paid! (All said without knowing any of your circumstances - sorry).
Mobile is not a problem in Joomla - just a case of template.
As far as whether or not it is an “app”.
Having read in the forum so much about the problems of getting 4D apps validated (whatever) by the respective stores there is the alternative (of which I have only learned - yes I am behind the curve) of “progressive web apps” which would seem to be the “on trend” way of getting your “app” onto a 'phone without the trouble of validation. Again I haven’t investigated this (I only learned of pwa’s last week!) but a quick shuftie at Joomla’s extensions and there is indeed offerings to enable this internally to the CMS.
Slightly more than tuppence’s worth and it may be totally irrelevant.
But there is the saying “To a man with a hammer everything’s a nail” and it may well be that re inventing the wheel in this case is not necessary.