Hi there. I know a reseller where you can add your NS-servers for the domain and also modify the IP in the A-records right from their dashboard. What would happen if I did that?
Will the website still be accessible? I'm asking because I don't want to wait 24-72 hours if something goes wrong.

When you change the NS (Name Server) settings, you're essentially telling the world which DNS (Domain Name System) servers are responsible for translating your domain name into an IP address. The NS records point to the DNS servers that hold the DNS records for your domain. These records include things like A-records (which map your domain name to an IP address), MX records (for email routing), and more.

Now, if you decide to change the NS-servers, you're basically moving the responsibility of managing your DNS records to a different set of DNS servers. This can affect how quickly your website will be accessible again, because DNS changes usually require propagation time. DNS propagation is the process of updating and spreading the new DNS information across the internet. Although the industry standard is 24-72 hours, in many cases, changes may start reflecting within a few hours or even minutes. But keep in mind that this is not guaranteed, and during this propagation period, some visitors might still be directed to the old server.

As for changing the A-records, this is more straightforward. The A-record points your domain to a specific IP address, which is where your website's files are hosted. If you update the IP address in your A-records, you're telling the DNS servers that your website is now located at a new IP. This change is usually faster to propagate because you're not switching DNS providers; you're just updating a record on the existing DNS server.

If something goes wrong, and you need to revert the changes, the key factor is how fast the new information propagates. While DNS changes can take up to 72 hours to fully propagate, the changes often take much less time, sometimes just a few hours, depending on the TTL (Time to Live) settings of your DNS records. The TTL tells DNS servers how long they should cache the information before checking for an update.

So, will your website still be accessible? In most cases, yes, but it might not be immediately. The old settings could still be cached by ISPs or end users, meaning they might continue to see the old version of your site or experience downtime until the new settings propagate.

To minimize downtime, you could lower the TTL of your DNS records a few hours or even a day before making any changes. This way, when you make the change, the DNS servers will check for the update sooner, leading to faster propagation. Just remember to set the TTL back to a higher value once the changes have been made and everything is working correctly.
If you change your NS-servers and A-records, your website will eventually be accessible, but there could be a delay while the changes propagate. To avoid the 24-72 hour waiting period, you should plan the changes carefully and monitor the propagation process closely.

You've got just 2 choices:

Use the registrar's DNS settings and set the A-record to point to the right IP address from your hosting provider.

Go with the hosting provider's DNS directly.

Pick one.
Make sure to update your DNS records promptly after making a choice to avoid any downtime.

If your LC is a hosting server control panel that the domain is tied to, then setting either NS or A records will have the same effect. Any combo of those will work just fine.

But, if your LC is more of a domain registation panel, then setting the hoster's NS will essentially override the A records you put in this panel. Sure, you can add them, but they won't really function. To make A records active, you need to point the NS to the DNS service where they're set up, and they'll be active there.