there are tools so that you do not need it, but well its not supported.
in recent updates there is a new supported scenario, you can remove the exchange but you need to keep the schema and powershell modules and than you do everything with powershell
Well there is aad connect and aad connect cloud sync. Btw I still don’t get it that they have no solution to remove the last exchange server. It can be so easy to make it work, but well…
there are tools so that you do not need it, but well its not supported. in recent updates there is a new supported scenario, you can remove the exchange but you need to keep the schema and powershell modules and than you do everything with powershell