@Bonus12 Thanks for reaching out.
The redirection that you are seeing now is because going forward MS decided to give you a unified experience of your all M365 security ecosystem at one place.
This was announced in April 2021 : https://techcommunity.microsoft.com/t5/microsoft-defender-for-endpoint/welcome-to-microsoft-365-defender/ba-p/2436618
https://techcommunity.microsoft.com/t5/microsoft-365-defender/unified-experiences-across-endpoint-and-email-are-now-generally/ba-p/2278132
For the tenants which has not been migrated, they will see this banner on securitycenter.windows.com :
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