On desktop I use Mercury Browser - a Firefox fork - but I'm not sure how " privacy focused " it is other than that it's Firefox based
On Android I use Brave Browser , because it meets my needs , while it was good compared to other browsers in privacy tests , I still won't recommend it 100% for privacy for the following reason ( unless you're ok with changing some settings to make it more private ) :
If you care about your privacy , you can read this browser check series for both desktop and mobile ( in German , you might need a translator ) by security expert Kuketz , the rest of the browsers are linked in the same page