Updating app that were downloaded with a different apple ID
Not sure what advice you are looking for really.

To update apps downloaded with a particular Apple Id needs the password for that ID.

Perhaps you should have done a "factory reset" and established your own Apple Id from the start. Do not reset until you’re ready to walk away from all the apps you can’t update. You will need to repurchase them, go without or find a substitute app that is available in this case.