I wiped everything related to RS3, reinstalled again today, downloaded cache fresh (about 40 minutes), reset graphics (another 15 minutes).
Everything looked good, seemed to be working smoothly. Played about an hour (which is longer than I had been going). In the middle of a clue, solving a puzzle box and it crashed again out to login screen. No error message yet this time.
09-Oct-2022 17:52:00