Searching for phpmailer alternatives

I have created an online assessment tools for hiring candidates.
The website is built on php.
I want to explore EMAIL INTEGRATIONS for our website, for sending exam links to the candidates except for phpmailer since I need to send more than 150 mails/per hour
(150 mails/hour is the threshold of phpmailer)
I am searching for some good alternatives.
It’s not an issue if I have to make a payment for them.