I just report two problems I have with all versions above the 53 version of Opera.
I always have 130 open tabs and with the 53 version of Opera it is not a problem. But with all versions above 53, including the Beta 63 version, I always have 100% CPU occupancy, even after all tabs have been fully loaded, making the computer unusable because he is very slow. With version 53, processor occupancy normally drops when all tabs have been loaded and oscillates between 5 and 10%. I specify that I use other browsers, Chrome, Brave, Firefox, Vivaldi, but Opera is the ONLY browser that has this problem. The only solution I found to be able to continue using Opera, which is my favorite browser, is to use version 53 and disable automatic update. It works, but I wish I could use the newer versions of Opera.
It's also impossible for Opera not to load all the tabs entirely, while Firefox allows it, which speeds up the opening of the browser a lot. Firefox opens in seconds, while Opera takes more than 4 minutes and fully loads all tabs unnecessarily. Firefox only loads a tab if you click on it.
My computer is a 27-inch iMac 2011 i3 3.2 GHz with 16GB of memory with High Sierra and that works perfectly.
Thanks for your help.