Custom Code to translate "Yearly" and "Monthly" in the Pricing blocks

You will need to add the following code to the page Settings ->Custom Code → Header area → Save → Publish:

<script>
window.addEventListener('block-loaded-pricing1', () => {
          $("span:contains('Yearly')").text('aaa');
          $("span:contains('Monthly')").text('bbb');
});
</script>

Thanks for this.
Wondering if it would be possible to create 3 options (eg Monthly, Quarterly, Yearly) somehow too?

Currently, it is not possible to have those 3 options using custom codes as this functionality is not supported by the pricing blocks. However, I will add your message as a suggestion to our feature requests list to consider when planning further app updates.