Chromium 84 fails to install, Firefox builds later than 53

This is the output from Chromium 84, extracted manually:

[1014/092356.220:ERROR:registration_protocol_win.cc(103)] CreateFile: The system cannot find the file specified. (0x2)
[1014/092356.955:ERROR:crashpad_client_win.cc(132)] crash server failed to launch, self-terminating
[1014/092356.986:ERROR:registration_protocol_win.cc(103)] CreateFile: The system cannot find the file specified. (0x2)
[1014/092357.189:FATAL:exception_handler_server.cc(277)] GetFileInformationByHandleEx: The handle is invalid. (0x6)
[1014/092357.189:ERROR:crashpad_client_win.cc(132)] crash server failed to launch, self-terminating
[1014/092357.439:FATAL:exception_handler_server.cc(277)] GetFileInformationByHandleEx: The handle is invalid. (0x6)
[1014/092412.440:ERROR:registration_protocol_win.cc(103)] CreateFile: The system cannot find the file specified. (0x2)
[1014/092412.721:ERROR:crashpad_client_win.cc(132)] crash server failed to launch, self-terminating
[1014/092412.924:ERROR:registration_protocol_win.cc(103)] CreateFile: The system cannot find the file specified. (0x2)
[1014/092413.096:FATAL:exception_handler_server.cc(277)] GetFileInformationByHandleEx: The handle is invalid. (0x6)
[1014/092413.096:ERROR:crashpad_client_win.cc(132)] crash server failed to launch, self-terminating
[1014/092413.425:FATAL:exception_handler_server.cc(277)] GetFileInformationByHandleEx: The handle is invalid. (0x6)

Likewise, Firefox builds later than 53 do install but do not launch with the required compatibility mode set. Firefox 53 seems to be broken for me, launching fine but won't display anything.