Of course, there can never be absolute security and you should always be careful whether the websites you visit and the downloads you make seem trustworthy. Of the browsers on offer, Mozilla Firefox is currently said to be the most secure. Chrome and Edge require small additional measures, but are also considered safe, only Internet Explorer is outdated.
The Opera browser is also considered secure; it scores points above all with a free integrated VPN. Which of these browsers you ultimately choose is probably a matter of taste - the only important thing is that you set it up securely.
In order to protect your browser, you should always install the latest security update immediately, often there is a function in the browser settings that does this automatically.