I wouldn’t try to bend the Tor Browser to fit this use case for reasons already explained here:
The same problems appear when using the Brave browser, so the issue is probably the invasive code of the website.
If you really need to access web.whatsapp.com through Tor, I would recommend Tails. It is the easiest and safest method, but also the most resource-intensive and inconvenient. You can also do something similar to what Tails does with your own virtual machine or container, although this approach is more difficult and error-prone.