Hi @Vio_hal, welcome to the community. You can achieve this via IFTTT + Rule Engine HTTP Trigger.
Frist to create a rule and add a HTTP Trigger. Add the desired actions in the Flow, and copy the HTTP Trigger URL.
Then go to IFTTT.com and create an IFTTT applet by using “Date & Time” → “Every month on the” as the IF section, and Webhooks as the THEN section. Fill in the URL copied from previous step. Then this IFTTT applet will start the rule you created in Rule Engine on the specific day of month you specified.
Meanwhile, if you are interested in this feature to be natively supported in Rule Engine, please cast your vote in the following feature request.
Feel free to let me know if any questions.