Correct me if I am wrong please. Aren't relay email address with custom domain more prone to spam? If I give my email *@<fixedCustomDomain>.mozmail.com to a sp

Correct me if I am wrong please. Aren't relay email address with custom domain more prone to spam? If I give my email *@<fixedCustomDomain>.mozmail.com to a spammer, now they know the custom domain I own and can spam me on infinitely generated aliases on this domain e.g. by sending emails at <infiniteAliases>@<fixedCustomDomain>.mozmail.com? This is such a simple exploit.