SMTP and Floating IPs

This page on floating IPs, and others like it, explicitly say “Floating IPs do not support SMTP traffic”. The only reason I use a floating IP is for SMTP. Consider, we get a droplet from DO that has already been abused by a previous client who setup a mail server for spam. The IP is on a blacklist and we need to go around begging the listkeepers to remove the IP address. Now we have a clean IP and run for some period of time without issues. Then let’s say the droplet dies and we need to replace it. If we need to get a new IP then we may need to repeat the pain of getting off of lists. But if the mail server is run on a floating IP we can re-use that same IP and there’s no related grief!

So, is there a way to prove to DO that I’m not a bad actor so that I can run SMTP on a floating IP? I have a valid mail server already in use. No black marks on my domains. I just want to port from a competitor DO, do this dance with a DO IP just once, and then have that small peace of mind if things go south.

And yes, all of this is based on experience, not conjecture. Thanks!