Hi.
Wappler has no lock-ins. And you will find many posts in this community comparing Wappler & Bubble, and also about people completely new to coding & web apps - reading through them will give you a good idea of how things work with Wappler.
You do need additional plugins - called custom module or extensions - for specific use cases, for eg: creating a PDF from HTML. But for most general operations required in a small to medium complexity web app, built in components/plugins are enough.
Like mgaussie has suggested, knowing JS helps a lot on the client side of things and allows integrating third-party libraries which allows for greater functionality in your app. And if you are building a NodeJS app, its also helps on the server side.
To begin, I would recommend you to refer various tutorial out there on HTML, JS & CSS. Built something small. Maybe a 4 page static website. Then learn a bit about SQL (MySQL or MSSQL or Postrges…) and implement it on the sample website. Next, read up a bit on servers - PHP & NodeJS.
Once you understand these languages & understand what the role of servers are, you should take a look at @mebeingken’s excellent Getting Started course & various other docs & videos as shared by Ben - which are all about Wappler.