If you want to learn CPR, the Disque Foundation allows you to take the class for free and attests to be aligned with the current ILCOR protocol (you might catch minor discrepancies). Before you pay them though, know that for certification institutions generally require an AHA or ARC issued certificate.

CPR: https://disquefoundation.org/cpr-first-aid-aed-certification...

BLS: https://disquefoundation.org/bls-certification-renewal/

To become certified, you can do the AHA HeartCode adaptive class online in about an hour, followed by a 10 minute skills test on a Voice-Assisted Manikin. The manikin simulations guide you with incredible feedback on depth and rate and have come a long way from the old style of dummies. Conveniently, these are in self-serve stations across the country (often in an office space near your local hospital that you let yourself into with a combination code).

Also, some of the more useful learning tools are the animated visualizations showing the physiology involved such as https://youtube.com/watch?v=9QPwrVIBMvY — these help learners conceptualize how the first few compressions are not effectively circulating blood but are instead building up pressure (which helps them understand why continuous compressions are considered by healthcare professionals when there is not yet an advanced airway and used after there is — https://www.ahajournals.org/doi/10.1161/CIR.0000000000001369...).