How to provide service access in multiWAN conditions from a domain name?

Question

Domain Name System

There is network equipment configured to switch two WAN channels from different providers (mikrotik).
There are services of various motleyness: sites, FTP, software, something for internal use, something as a service, something business cards on the net, something hybrid.
In conditions of channel switching, for example, a website that is hosted on its own facilities needs to somehow indicate to the outside that the IP address has changed. OK, let's say the domain registrar has several entries with two pre-registered white IPs from our providers, but only one entry can be active. Until the records are updated, time will pass, and the service will not be available. Well, as I understand it, here is all the linkage to TTL. If a third-party Vasya, who is not connected with me in any way, just found my site on the Internet from another region, tries to connect to my mysite.com, he will get a fig, because there is a record on the old IP, but the records have not yet been updated on the new IP. As far as I understand, even if we can manage the TTL at the domain registrar through the issued LC, then what's the difference, the rest of the DNS have their own record lifetime, on which I can knock on them so that they update the record. That is, conditionally, the hour has not come out, the third-party DNS will tell me "go for a walk, an hour has not passed for you, an hour will pass, then you will come and knock, I will write down that you have a new IP."
Actually the question is, how is the issue of resource availability by domain name solved when switching providers? Transfer to hosting is not considered in this case.

Answer 1

OK, let's say the domain registrar has several entries with two pre-registered white IPs from our providers, but only one entry can be active.

Wrong.
Google "dns round-robin configuration".

Answer 2

if I understood correctly, ip / cloud in micro + CNAME-records from the host

Answer 3

Failover remote access, is it possible under the following conditions?

Answer 4

Set up the simultaneous operation of all providers and register their A-records in DNS, as mentioned above, this is called dns round-robin.

Answer 5

This is for two channels to be active at the same time https://www.youtube.com/watch?v=Gwl-0bRxOY4
Well, above they offered cheap and hearty CNAME + ip->cloud