i have been testing german market a little- until now without problems. But haven’t tried out all functions tbh. Can’t speak for germanized. But if i’m right the latter offers a basic free edition – so maybe just give this a try to check out.
GP uses the default Woocommerce templates, so if the plugins you’re looking at are 100% compatible with woo then they should be too with GP.
The only caveats too this would be some of the functions GP Premium adds – such as the Mini Cart and the Add to Cart Panels. These may not translate directly but i am sure we could assist if that is the case.