Finally some solution for those annoying page crashes, thanks!
For those who use Ubuntu/Debian based distros, I created a simple deb package for myself with Opera fixes (ffmpeg, widevine/DRM), feel free to use it: https://github.com/swanux/opera_codecs
(For automatic updates you can add my PPA as described here: https://swanux.github.io/hrepo.html)