Powershell Expert for Organization-based 0365 Exchange

I just moved multiple accounts/domains over to one Microsoft 365 business account. The separate domains for the other accounts turned into secondary domains to the main tenant domain. Then the emails from those domains become added alias. We made this change because as the business grows the employee cant always be requested to have multiple accounts. It has become pricey and troublesome keeping up multiple accounts. Due to the alias change all the emails go to one inbox now. I have tried seperating them based on folders and OWA rules but it always goes to first rule. I believe the alias emails are seen as the primary one regardless of ruleset. I want to create I powershell script to for exchange to create new folder, redirect alias emails to those folders, and force reply from priority to that email it was from.

Create folders;
Create new folder organization or domain wide > MainTenantDomain
Create new folder organization or domain wide > Domain1
Create new folder organization or domain wide > Domain2

Send to folders;
Then if From * MainTenantDomain.com Send to folder MainTenantDomain
Then if From * Domain1.com Send to folder Domain1
Then if From * Domain2.com Send to folder Domain2

Respond with correct email or alias;
Then if From * MainTenantDomain.com response priority * MainTenantDomain.com
Then if From * Domain1.com response priority * Domain1.com
Then if From * Domain2.com response priority * Domain2.com

https://docs.microsoft.com/en-us/powershell/module/exchange/new-mailboxfolder?view=exchange-ps

Have more projects if happy with results, but this is priority right now!