The screen is stuck with the "Create Blade" message.
Tried both on Chrome and Edge
I don't know why is this happening to you. It's working fine for me.
If you still not able to make it work. Make sure you have enough amount in your Azure subscription (or) your subscription is Active.
However Azure Portal is a simple GUI to create any resources easily. But it doesn't mean to stop you from using other ways like Azure CLI, Powershell, ARM templates, Other SDK's
Azure CLI to create a WebApp Bot
Dot Net SDK to create a WebApp Bot
Node.js SDK to create a webApp Bot