I was on the free tier so I don't know for sure, but I believe the whole point of the dedicated IP offering is you are the only customer who can use it. So lon

I was on the free tier so I don't know for sure, but I believe the whole point of the dedicated IP offering is you are the only customer who can use it. So long as your SPF records reflect just that IP SPF will remain in force if someone tries sending through one of the shared IPs as you. But if moving isn't a huge deal, there are plenty of recommendations in these comments of alternatives.