you should remove the vb forms. the resource file is the same for both.
but if your goal to run on the iPhone, then you need to redo the forms anyway. winforms (or WPF) is not supported on non-windows o/s's (iPhone)
you should create a new Maui project, and build the new forms with Maui xmal. You can copy some of the code behind, but it will require changes.
hopefully, you used separate projects for non UI layers, but if not, you can just copy the code to the new project.
https://dotnet.microsoft.com/en-us/apps/maui
note: while you can develop Maui apps on windows, you will need a Mac with Xcode installed to actually build and test the iPhone app. You will also need an apple developers license ($99/year) to sign and run the app.