the problem you mentioned is pretty common, it happens with me too, Try clearing the Cached data with the help of GX Cleaner, make sure you select "Everything" option. Also, if this problem keeps occurring continuously, you can try Re-Installing Opera GX. Also, all the browser crash, but if they start crashing like everyday, that makes a problem, so if the above tricks don't work, you can try reporting it directly via Customize and control Opera > Help > Report and issue.