Tired of putting in air

I have a Rubbermaid brand lawn/atv dump cart that has Carlisle “AT20X7-8 4 MAX “tires, tubeless on 9 inch rim (one piece). Very new tire, but one has two small cuts in sidewall. I considered taking tire off and patching from inside. Worthwhile? I attempted with some effort to get the tire off the rim but no luck so far. If a patch is out of the question, what would be my other options? Install a tube? Or new tire (last resort)? I’ve sent an email off to Carlisle and posted to their Facebook page in hopes of a prompt and worthwhile response.