Btw… you don´t need Secure Boot to start Windows.
Disabling Secure Boot
The concept of such a system is not bad in itself. However, as is almost always the case, the monopolist’s implementation is atrocious and is designed only to exclude other systems.
Either you install Garuda with Secure Boot (I don’t know if the guide is up to date) or you disable it completely. Everything else remains piecemeal and error-prone.