I guess that is more likely the case but at least it gives us an enhanced privacy as compared to using a normal browser without VPN.
No, it doesn't. It probably makes your privacy worse. Instead of all your traffic simply going through your ISP, you are instead routing all your traffic through Opera's server. They openly admit that they monitor it all, keep logs, pass that data to advertisers, and use it to target you with ads. You'd be better off not using it all.
Afterall, I understand no one is 100 percent safe even with the best security setup on their systems.
Sure, but not being able to achieve 100% safety isn't a reason to expose yourself to unncessary risk. Would you drive with no seatbelt just because you can't be 100% sure you wouldn't die in a crash anyway?
Yes we can disable their permissions but for using an app like facebook and instagram we have to give those permissions or else we can't upload anything
Good. Stop uploading things. Stop using social media altogether. It is a massive invasion of privacy. If you absolutely can't resist the urge to post stupid selfies and pictures of your food, then do so from a dedicated device that is not linked to any of your crypto activities.