Hi,
For renewing SSL certificate used for essential server, kindly check the steps shared by TDell987 in below link.
He mentioned when choosing the 'use another domain or domain name service provider' option even though you don't want to do either of those things. This will offer the opportunity to use a personalised .remotewebaccess.com domain. So you follow that and surprise, surprise you are asked whether you want to use the existing myserver.remotewebaccess.com domain or create a new one or pick another you have created earlier.
Details could be found here:
Server 2016 Essentials - remote access certificate expired
https://social.technet.microsoft.com/Forums/en-US/9419502a-45b1-429b-a750-fdfb743155fb/server-2016-essentials-remote-access-certificate-expired?forum=ws16essentials
Kindly check above details and verify if the option here will be helpful.
Hope this helps and please help to accept as Answer if the response is useful.
Thanks,
Jenny