Relentless is a good word for describing something that’s harsh, unforgiving, and persistent, like the hot sun in the desert, or a cold that keeps you in bed for days with a nose like a strawberry. When you’re relentless about something, you mean business. https://www.vocabulary.com/dictionary/relentless

Someone who is relentless is determined to do something and refuses to give up, even if what they are doing is unpleasant or cruel. https://www.collinsdictionary.com/us/dictionary/english/relentless

10 Powerful Quotes About Being Relentless https://supplementreviewslab.com/10-powerful-quotes-about-being-relentless