Hi,
Maybe you could refer to this link:
https://learn.microsoft.com/en-us/answers/questions/56332/choosing-sbs-version-2019-or-365.html
And since server essentials 2019 has been removed "server essentials experience"role and "RDgateway" role,so if you still want to use either role, I recommend you to purchase server 2016 essentials product.If we only can purchase server essential 2019 ,we can try to contact Microsoft Licensing Activation Centers support to downgrade it to server 2016 essentials.
https://www.microsoft.com/en-us/licensing/existing-customer/activation-centers
Hope this can help you!
--please don't forget to Accept as answer if the reply is helpful--