How does Geolocation Route 53 and DNS caching behave when the server IP address changes?

Question

Domain Name System

I have very little experience in administration, so my question may seem silly. Sorry in advance.

My site uses Geolocation in Route 53. That is, I specify for each user region - the IP address of the server. For example, users from Japan go to server1, users from the US go to server2, and users from Europe go to server3.

So far so good, but I'm worried about the risks if something goes wrong with different servers. As far as I know, DSN records are cached on the user. Because of this concern, I have a few questions:

1. What happens if server1 or server2 goes down? Will Route 53 redirect to server3? Or will it not do this automatically and do I need to somehow configure Route 53 additionally?

2. What happens if the IP address of server1 changes? In the DNS, of course, I will specify a new IP for Geolocation with the Japan region, but if the DNS is cached, then a user who visited the site a week ago from Japan will not be able to get to the site today. Right? That is, I believe that the old IP address of my server will be stored on his computer (cached), and this is where the request from the user's computer will go. That is, he will not know that the IP address has changed. Do I understand correctly? And if so, how should it be corrected?

Answer 1

but if the DNS is cached, then a user who visited the site a week ago from Japan will not be able to get to the site today. Right?

Not quite right. https://www.google.com/search?q=dns+ttl
and the first link from the search results:
A detailed guide to setting TTL for DNS records