If I were to host this myself, I'd still need a static IP that had a good reputation. GCP and Azure both mention that we should not be hosting mail servers on t

If I were to host this myself, I'd still need a static IP that had a good reputation. GCP and Azure both mention that we should not be hosting mail servers on their platforms (rather, they all suggest we setup mail servers + relays to a reputed IP). How would I go about getting a static IP or a reputed IP?