The same could be applied to workflows. I have very little expierence with workflows, but assuming they have a timestamp from when it is being assigned to someone you could also set a lastRemindDate at the same time, you could run a microflow in a scheduled event for example every hour that checks if there are workflows where there is a lastRemindDate’ with daysBetween($WorkflowTask/lastRemindDate, %currentDate) > 7.
This would provide you with a list, then use that list to create a flow that emails the assignee with a reminder to sign their workflowtask. After that is done you set the lastRemindDate to CurrentDate to avoid spamming people. Of course you can play with these parameters however you'd like.
I think scheduled event would work fine for this.