The Chromium versions that Opera 96 (and newer) builds use require that the SetProcessMitigationPolicy function is present in kernel32.dll. It's not present in the version of kernel32.dll that Windows 7 uses, so things break. And, that's just the first error. There could be more if that one was somehow fixed.
The situation sucks, but, like other Chromium-based browsers, Opera no longer supports Windows 7 and 8.1. The decision has already been made for all the browsers. Your only chance is if someone comes up with some patches for Windows 7's components similar to how https://kernelex.sourceforge.net/about/ did for Windows 98.
