Do I need to lower TTL of all records

Hi,

You're correct that lowering the TTL of the NS record is sufficient. The Route 53 Developer Guide includes a detailed process for migrating DNS to Route 53:

https://docs.aws.amazon.com/Route53/latest/DeveloperGuide/migrate-dns-domain-in-use.html

Actual hands-on work doesn't take long unless you need to create a lot of records. However, if you follow the entire process, it'll take a couple of days altogether because you need to wait for the TTL to expire on the NS records. Customers who have used this doc to migrate DNS for active websites have reported success, including with keeping their website up the whole time.

Scott