If you are buying a domain through Route 53, there is a good chance the purchase is actually being handled by Gandi[0]. Gandi supports DNSSEC[1] (it's literally a check box in the options, very simple) so you may as well skip buying the domain through Route 53 and get it directly from Gandi.

No affiliation with either company, just a happy customer of both.

  [0]https://aws.amazon.com/route53/domain-registration-agreement/
  [1]https://docs.gandi.net/en/domain_names/advanced_users/dnssec.html