You mean ads that appear when you launch the apps? (to me "startup apps" means "apps that run when you start the phone). Are these things popping up when you get a connection, or just when you launch the corresponding app (Opera or Copilot in the examples you have given)? If the latter then it's within the app, and your only option is to find a setting (if any) in that app. If you are getting pop-ups without opening a particular app your problem is that you've installed some adware: it's one of the apps you've installed that's causing these, and you need to identify which one and remove it. If you get this just when you open a browser then check the browser's settings (to block pop-ups) and clear it's cache (in case there's an ad script in there).
The best ad-blockers require root, but there are some that don't. Those you can find in the Play Store will only block ads in browsers from what I've seen, but there are things outside the Play Store (DNS66 from the F-Droid store, or an Adguard variant you get direct from them) which will block ads more widely (using a VPN to filter them out). Not as effective as the versions that need root, but might help.