Can Ads Manager pause ads that are spending money but not selling?

Yes, with a rule. Go to Marketing → Ads Manager → Rules. Start from one of the template buttons, or click New rule.

• When ALL of these are true: add up to 5 conditions, for example ROAS below 1.
• Over the last (days): the period to look at. Today is not counted.
• Only if it spent at least (optional): skips things that spent too little to judge.
• Then: Pause it, Turn it back on, or Change daily budget.
• Mode: Suggest adds the change to Recommendations for you to apply. Automatic only acts if your Settings allow it.

Tick Rule is on and click Save rule. Rules run once a day. Click Preview to see what a rule would match right now.