You need to step back and make sure you understand the basics here.
Styles and registrations are not the same. You can’t convert because they do completely different things.
Styles are files which you select to play as your accompaniment. Style files will normally work on most Yamaha arrangers including CVPs, although there are voice and effect differences between models which may make them sound a little different or need a little adjusting. But mostly they sound ok.
Registrations (usually .rgt) are files which can store many of your keyboard feature selections and settings - including voices, styles, effects, various features like pedal settings - so you can instantly recall them. But they do not contain any of the actual files - the style or the voice or effect. They just store the information on what you used, and where they are stored. Since they need to know exactly what you used and where to find it they are often quite keyboard specific. The registration file you import might refer to a style you don’t have, or even if you do, it may not know where to find it. A very common mistake new arranger players make is to import a registration which points to a custom style but not to also import the custom Style. And even if they do, you also
have to re-do the registration to tell it where that style is stored.
The other thing is that the way Yamaha systems work you need to be in the right area function of the keyboard to see specific files. You cannot view voices if you are in styles. You cannot view registration files (.rgt) unless you first select registrations. You cannot view style files unless you select ‘styles’.
I advise you to take some time and read through the various sections on the PSR Tutorial to learn about styles, registrations, voices etc. Not the forum. You get to these by clicking the PSR Tutorial at top right of the forum index page, then follow menus.
Mike