hey @w.fly I am a newbie to Wappler with more than 3 years with Bubble and have removed for the same reasons you have detailed.
Wappler will help meet your requirements and you do have access to the code and now they support Nodejs it is a more viable proposition.
A couple you things to keep in mind, as others have said it is a steep learning curve and will take you a month or two to get up to speed. There are a few frustrating things about Wappler, but just ignore them and try and work around them. I am sure the Wappler team will eventually work it out for themselves (a bit like the bubble guys in the early days) but at this stage they have a focused view, which is not necessarily a bad thing.
This is not like the Bubble community, although they are very helpful to point out the errors in your ways The majority of users have a history elsewhere, so make sure you are very specific in your questions and with a background in PHP and MYSQL it should serve you well!
In your first weeks of discovery just post your questions here in the Bubble to Wappler community as we understand what you are trying to transition from.
I would spend some time learning bootstrap, the visual designer is really rudimentary and pretty much just a preview tool and you are far better learning bootstrap and coding the html and css using a combination of the available Wappler bootstrap elements and custom css.
Overall after a vast search online for other alternatives, Wappler is the best of a new set of tools hitting the market at the moment. I am sure it will get better, and I am sure that other tools are on the horizon, but from my own research the code Wappler generates for you could be ported else where if better tools become available. Not that you would want to, but it is good to know that you are not locked into one provider.
Overall, I would say give yourselves a 12 month commitment with Wappler what everything you create belongs to you.