This should neither be buried in dev tools nor filtered through extensions. It should be a visible built-in and with the click of a switch - JavaScript are disabled.

Opera should let we (the users) to add and remove sites that JavaScript blocking will be excluded. If a site deserves trust, we (the users) should have the option to whitelist it. But JavaScript blocking should not assume trust by default. That’s outdated thinking.

Advanced users are tired of getting sandboxed by browsers afraid of offending ad tech. If a site breaks without JavaScript, that’s the site’s fault. Let it break. Let users decide what to permit, not the browser.

Right now, Opera is feature-rich, but this is a missing feature. Brave users can block scripts. Firefox users can too. Why not us?

It’s time to treat privacy as more than a marketing slogan. A script-block toggle is not a luxury, it’s a necessity.

Here are some benefits of JavaScript blocking:

• It blocks malicious, slow, or spying scripts in real time.

• It dramatically improves page load speed and battery life.

• It stops unnecessary CPU drain and memory hogging: This is beneficial for older devices or low end devices like my Galaxy A05s.

• It allows per-site control — power users can tailor their browsing experience.

• This will reinforce Opera’s commitment to privacy and performance.

In a world where cybercrime is prevalent, we need to protect our data so well so that we will not be the targets of cyber-criminals and it will be hard for cyber-criminals to access our data even to the barest minimum.
Privacy matters a lot.

The option would be in site settings, but it doesn't exist.

По сути нужен удобный лаунчер закладурок, расположенных в панели закладок или локально.

Например вот такой "Script Menu", но мне не понравилось его куцее исполнение.

Hard to say without a JS demo showing the problem.

Would that work?