The Brave browser apparently blocks cookie consent pop ups by default. I'm not a user so can't vouch for its effectiveness.
Alternatively, there are Firefox add ons that can block cookie consent pop ups, just search for cookie consent in the
Firefox add on page.
On a side note, if you reject all cookies a lot of websites will set the cookie consent cookie expiry to a ridiculously short period. I've seen as little as a week but a month or two is quite common. That means that you will continually be pestered to accept all cookies every time the consent cookie expires. If you install a cookie editor add on you can scroll through each cookie for a website that you visit regularly and set expiry dates to 20 or so years in the future. Bit of a faff but once it's done it's done.