I’m a warlock main and completed Renegades campaign completely before starting it on the other two characters. For both of those characters, seasonal artifact selections reset regularly even after completing the campaign with them, although the intervals vary: immediately after setting them; after an activity completes; when going from the tower to orbit; during an activity; traveling from one destination to another (eg Tower to Tharsis). In particular, this prevents me from using any of the artifact mods in activities, including Lawless Frontier.