It's not startup if it's already running. You mean running it from the console, or clicking an icon or menu item somewhere ... and which desktop and distro?
I know some sites presume when they see Opera for Linux that it is really Opera for Android set to identify as a desktop version, Not a new issue and nothing Opera is doing at all... only answer is to have a useragent switcher identify you as either Chrome or Opera on Windows.
It seems like it was some damaged file from my /home/username because I created a new user (and I'm using it) and it hasn't crashed since that. Don't know what it was exactly but it works now 🙂
Go to deviantart, search for "start page" (with and without the space between the words), pick the one you like, download it on your system, modify it so as to fit your needs and then open opera, go to settings > basic > on startup > open a specific page and set it there like so
Right click the place where the image should be.
Inspect element.
Near the opened elements, you should find a canvas with a width and height of 264 pixels. It also has a style attribute: "display: none"
Remove the style attribute by double clicking on the attribute and press delete or backspace.
Press enter to confirm this change.
The QR-code should now be visible.
fix the whatsapp web QR
If it doesn't work the first try, refresh the page with Ctrl+F5 and try again.
Please read the thread in my signature. It answers every single question you have, including the why you should NOT install something made for another distro.