Beta 82.0.4227.7 on Linux x64 crashes here ("Seite abgestürzt") on e.g. Google Mail (about a second after loading) or WhatsApp Web (before loading) since the update.
81.0.4196.54 works.
Tell me if I can support debuggig.

Right, it seems to be the libffmpeg workaround. I am using the workaround from https://forums.opera.com/topic/37539/solving-the-problem-of-the-opera-browser-with-video-playback-in-ubuntu-and-similar-distributions-linux-mint-kde-neon
Switching back to the original libffmpeg solves the crashes, but then some videos can't be played...

@rolandm-0: Correction:
Crash doesn't happen any more with https://repo.herecura.eu/herecura/x86_64/opera-beta-ffmpeg-codecs-96.0.4664.35-1-x86_64.pkg.tar.zst

This "stable" release causes the same crashes on Linux as described on https://blogs.opera.com/desktop/2021/11/opera-82-0-4227-7-beta-update/
Didn't happen with stable 81.
[711621:711621:1208/214235.414790:ERROR:url_pattern_set.cc(290)] Invalid url pattern: chrome://startpage/
[711621:711621:1208/214235.414935:ERROR:url_pattern_set.cc(290)] Invalid url pattern: chrome://startpage/
[711621:711621:1208/214235.414976:ERROR:url_pattern_set.cc(290)] Invalid url pattern: chrome://startpage/
[711621:711637:1208/214236.486536:ERROR:nss_util.cc(286)] After loading Root Certs, loaded==false: NSS error code: -8018
[711621:711621:1208/214237.049235:ERROR:CONSOLE(0)] "Unchecked runtime.lastError: Could not establish connection. Receiving end does not exist.", source: chrome://startpage/ (0)
[711658:711662:1208/214243.511589:ERROR:ssl_client_socket_impl.cc(983)] handshake failed; returned -1, SSL error code 1, net_error -100
[711658:711662:1208/214243.546840:ERROR:ssl_client_socket_impl.cc(983)] handshake failed; returned -1, SSL error code 1, net_error -101
Fontconfig error: Cannot load default config file: No such file: (null)
[711658:711662:1208/214244.532554:ERROR:ssl_client_socket_impl.cc(983)] handshake failed; returned -1, SSL error code 1, net_error -200
[711621:711621:1208/214255.452616:ERROR:CONSOLE(440)] "Uncaught (in promise) [object Object]", source: chrome-extension://obhaigpnhcioanniiaepcgkdilopflbb/message_handlers/linkdiscovery_message_handler.js (440)

@rolandm-0: After a reboot the error disappeared, OpenGL is enabled, Beta still crashes.
[12415:12415:1123/160509.998378:ERROR:url_pattern_set.cc(290)] Invalid url pattern: chrome://startpage/
[12415:12415:1123/160509.998520:ERROR:url_pattern_set.cc(290)] Invalid url pattern: chrome://startpage/
[12415:12415:1123/160509.998578:ERROR:url_pattern_set.cc(290)] Invalid url pattern: chrome://startpage/
[12415:12433:1123/160510.722714:ERROR:nss_util.cc(286)] After loading Root Certs, loaded==false: NSS error code: -8018

[626974:626974:1123/150046.011009:ERROR:angle_platform_impl.cc(44)] Display.cpp:894 (initialize): ANGLE Display::initialize error 12289: Could not create a backing OpenGL context.

@rolandm-0: happens with a clean restart after deleting config and cache, no extensions

Beta 82.0.4227.7 on Linux x64 crashes here ("Seite abgestürzt") on e.g. Google Mail (about a second after loading) or WhatsApp Web (before loading) since the update.
81.0.4196.54 works.
Tell me if I can support debuggig.

Could you at least tell us in the comments or log posts when you think the libffmpeg problem will be solved? I get tired of manually fixing things each time a new opera version appears when I could simply use chrome and not be bothered...

Still the bundeled libffmpeg.so can't play lots of videos (youtube, facebook etc.). Using the one from snap/chromium-ffmpeg now fails with "opera-beta: symbol lookup error: opera-beta: undefined symbol: av_stream_get_first_dts". I had to use the one from https://repo.herecura.eu/herecura/x86_64/opera-developer-ffmpeg-codecs-95.0.4621.4-1-x86_64.pkg.tar.zst (the opera-beta version there now fails like the snap version).
If you can't bundle a working lib like chrome and firefox do, at least make sure the snap version works, and have your installer install and link this!

Using https://repo.herecura.eu/herecura/x86_64/opera-beta-ffmpeg-codecs-93.0.4577.18-1-x86_64.pkg.tar.zst
solves the codec problem. What is wrong with the libffmpeg snap compatibility?

Right, it seems to be the libffmpeg workaround. I am using the workaround from https://forums.opera.com/topic/37539/solving-the-problem-of-the-opera-browser-with-video-playback-in-ubuntu-and-similar-distributions-linux-mint-kde-neon
Switching back to the original libffmpeg solves the crashes, but then some videos can't be played...