at dropbase, our focus was on enabling developers to get stuff done efficiently. we noticed that for 90% of internal tool use cases, you only need a table and modal to get user input. so we focused on developing those. while it may not be sufficient for external apps, for internal tools, it should cover most of that you need
What you compete with, what you have to beat, is not "something custom branded and more flexible". It's nothing at all. Cutting yourself out of that market with a tool that would easily be powerful and user friendly enough to fill this gap does not make any sense to me, if that is in fact your true reason. (And also I don't understand how that could make any sense intuitively if you just look at how often you see google forms being used by a big company as an external data collection tool).
It could be such an obvious differentiator for any of the competitors – but, like I said, I suspect the actual reason to why people are so ready to give up on this is rooted somewhere else.
For the patients, you might need submission process, you might need a place for people to see or cancel their next appointments, fill out a form or upload some pictures from other, while also making this information available internally, with doctors being able to document therapies and such.
Nothing fancy; I would hardly call it "build anything", it's all fairly CRUDy and on the face could be very effectively handled by all retool-alikes. (In fact budibase for example could have easily filled the need from a technical standpoint – but having to pay xx$ indefinitely per "customer" just does not work out, when you see most of them only once a year and maybe only once total, while having to keep records for many years.)
PS. CRUDy sounds like a fun and quite literal name for an app builder!