An easy quick win for securing Azure Active Directory passwords is the feature "Azure AD Password Protection". This helps you in mitre att&cks tactic credential access, for example in the technique brute force and its sub-techniques password guessing, password spraying, credential stuffing, etc.
Users are recommended to avoide simple passwords and instead should use pass-sentences. Password breaches of the recent past reveal that the majority still chose simple passwords. Azure AD Password Protection finds (audit mode) or enforces (enforce mode) stronger passwords for everybody. There is a hidden global banned password list which is applied to every user in the Azure AD tenant. Additionally you can block custom words like your companys name, your companys slogan, the founders or CEOs name, most used childerens names or your country or famous sport team names, which are often used as weak passwords.
Microsoft promises the "password validation algorithm" automatically detects/blocks variants and combinations like "password!1", "!password", "p@ssw0rd" and so on.
This is also available for on-premise Active Directory using an agent:
However this needs an additional license, you need to install and agent on your domain controllers, you need to reboot the domain controllers and you need Azure AD. Also you do not see the changing content of Microsofts global password list and there is no enforcement based on Active Directory groups or OUs, so you for example cant just enforce it to priviledged accounts but must enforce it for everybody.
Of course I highly recommend to use Multi Factor Authentication MFA everywhere.