On Pixel phones and other devices which don't support Dual Apps, you can create a "Work Profile". It is a completely isolated section of your phone and you can install another copy of Whatsapp by opening the playstore in your work profile.
It's there in Xiaomi and a few others. It essentially creates a separate sandboxed space for the entire phone. Apps, settings, themes, everything is isolated. Both the SIMs are accessible in either space.
On Pixel phones and other devices which don't support Dual Apps, you can create a "Work Profile". It is a completely isolated section of your phone and you can install another copy of Whatsapp by opening the playstore in your work profile.
https://support.google.com/work/android/answer/6191949?hl=en