Best way to send transactional emails from an InfinityFree website?

Hi everyone, I’m hosting a small PHP website on InfinityFree and need to send transactional emails such as contact form submissions and account verification emails. Since the built-in mail options have some limitations, I’m looking at using an external SMTP service provider instead. Has anyone here had good results with iDealSMTP or another SMTP provider on InfinityFree? I’m mainly interested in reliable delivery, easy PHPMailer integration, and any configuration tips that helped you avoid common SMTP errors. I’d appreciate hearing what has worked well for your projects. Thanks!