24 hours of intensive browsing and no more freezing for me.

Well, now I am very hopeful! I followed @Northnet 's lead and manually downloaded and installed the latest version 67.0.3575.31 (after doing a complete removal using synaptic package manager).

I have been surfing and browsing now for almost an hour with no freezing and no lockups!

It was interesting that I had to manually download the latest package from the Opera web site and use gdebi package installer to install it before Opera recognized it as an update. When I tried to use Software Manager it told me there were missing dependencies and packages required that would not be installed, etc. So I closed that and played a hunch by using the gdebi package installer, and it seems to have worked fine. It even said all dependencies were satisfied.

So far so good!

THANK YOU Opera devs for attention to this issue! Time to import bookmarks!

@Northnet
Not helpful for me yet, as I'm using LM 19.3 Tricia and my desktop is Mate 1.22.2 and
base is Ubuntu 18.04 bionic. When I click on the button to check for Opera updates it tells me my version 66.0.3515.103 is already up to date.

Maybe I have to uninstall and download again and see if I get a newer version.

Fresh install 19.3 Tricia (Mate) and brand new install of Opera, so it's the latest version. Mine freezes every 5 seconds or so. It still must be logging keystrokes and mouse clicks even though the screen is frozen. All I have to do is mouse over the "Easy Setup" button in the upper right and instantly everything I typed will appear or my mouse click will execute, pages will scroll, etc.

Does this on every web page I visit, no logic to it, just does it constantly no matter what. I have no other browser on my system.

I really need this to work. My ISP service is 500mbps up and down, and Opera is the only browser that lets me achieve any internet speed faster than 150mbps. Unfortunately, Firefox and Chrome are the only browsers I have tried (and removed) that do not ever freeze, but they are both incredibly slow and both keep my cpu pegged at 100%. When I use Opera the internet speed test will come back at 350mbps. But this constant freezing and mousing over the Easy Setup button makes Opera unusable for me.

This is such a pervasive issue for so many people I'm surprised that it isn't getting more urgent interest from the developers.