It’s still early days for FSE themes, making them great for simple experiment sites but not something I would double-down on for a larger project. The native blocks aren’t as functional and customizable as the equivalent features you find in themes like Astra. The navigation block used for building the header is one such example, and the Spectra plugin doesn’t offer a navigation block. The native navigation block works great for simple sites though.
If you want to build many templates, you’ll also run into consistency issues. WordPress blocks don’t yet support partially synced patterns. After many months delay, Spectra Pro started offering an equivalent feature called Globally Linked Styles but only for some blocks. Fortunately, they started with the blocks that are ready for use in-production on larger sites, i.e., the Heading block, the Container block and the Buttons block (my opinion).
The lack of partially synced patterns won’t be an issue if you only have a couple of templates to maintain (you can just copy the styles back and forth with Spectra’s style copier).
