I looked at the link you provided. I must say, as a dolt-level techie (74-year-old retired neurosurgical anesthesiologist) that the instructions appear VERY involved. I expected a simple on/off button but instead it's like something I'd find on HN....

It's overly wordy, probably for SEO reasons.

First, it's opt in. So you'd only need to opt out if you'd opted in at some point.

The instructions boil down to: Click settings, uncheck Brave Rewards button.

The rest of the article tells how to disable new tab background ads, remove the rewards UI, and how to do it again on mobile...but these are more personal preference things.

That is probably only cosmetic as the crypto related background processes will continue running and cannot be turned off. https://github.com/brave/brave-browser/issues/5429

I haven't installed brave in a long time, but maybe someone can try disabling the 'features' and check if these processes then turn off or not.