what if in App Store im signed into current ID but won't update apps unless sign into OLD ID?

No instruction from apple support on how to proceed if, in the App Store, (and EVERYWHERE else..) Im SIGNED IN to CURRENT Apple ID, (which is MY first & only ID) yet refuses to update SOME apps unless I sign in with PREVIOUS ID used on device (my mother's ID, as she upgraded to newer iPhone & I got hand me down.) I just wanna update apps! I'm signed into MY ID everydamnwhere I can think of in my phone, & have completed all steps I'm aware of to SEPARATE our two individual IDs with only limited success & am so frustrated I'm considering saying f-all & doing a gawdamn "factory reset," but oh let me guess, Apple doesn't do factory resets, peon! Back to groping blindly in the dark for whatever crucial *** feature or function tht we, Apple geniuses, have counterintuitively created silent & invisible to give our UI tht super cool & pretentious streamline look. ...GOD I HATE APPLE! HELP!