Definitely test your website and see whether sticky (fixed) navigation and headers are something that make your visitors want to stay longer and browse more of your content.
This time we’re putting masonry on the home page. Pho WordPress theme is a minimalist blogging theme with beautiful typography, lots of white space and the love for big featured images.
Speed is a what makes your website more usable, optimized for conversions, more enjoyable to browse and loved by search engine algorithms.
Figure out what you need, check out the official sources, free repositories for fresh and supported products and searching trustworthy sources and people connected to WordPress.org for recommendations.