As I was trying this, I uses Route 53, usually in zoho mail when I setup the domain for email it gives you step by step for what to put in records but not in Route 53. So there was a complaint that it keeps on going to spam / junk, right away I know I think that this has to do with SPF or DKIM (DomainKeys Identified Mail). To generate your DKIM in Gsuite in here then there's a button that says generate.
error - 400: CharacterStringTooLong (Value is too long)
I used 2048 that's why it's shows this, change to 1024 it will fix this issue.