I don't get why this is better. My approach:

const RESEND_DELAY_MS = 3600000; // because TTL in Agora

I would even go for

const RESEND_DELAY_MS = 3600*1000; // because TTL in Agora

Easier to check for the right number of zeros

Yes full agree

I've used stuff like this to do:

const ONE_HOUR = 3600000;

const RESEND_DELAY_MS = 2.5 * ONE_HOUR; // because TTL in Agora

IMO it makes it easier for successor to fiddle with.