I know we are supposed to use the UI, but it’s not ready for all purposes yet. Therefore it is nice to know that you can force the classic view for a little while longer. If for some reason you can’t use this approach, you can also change the URL like Jamie Bowman mentions here
https://admin.powerplatform.microsoft.com
Open Environment and then behavior and change the variable
Continue Reading Thomas Sandsør’s Article on their blog
Dynamics 365 force classic mode from admin panel
Blog Syndicated with Thomas Sandsør’s Permission