What would you propose as an alternative? To my mind, this is a pretty like-for-like experience with other operating systems, e.g. when you click an unknown file extension in Windows and it prompts you to pick the program to open it with. You'll get a prompt that says "How do you want to open this file?", you'll get a prompt to pick the program, and then there's a tick box that says "Always use program to open .XYZ files" It's reasonably intuitive to me.

And again, if you click "Always", the prompt never comes back again. I've unintentionally clicked Always once or twice and then had to spend some time in the Android System menu resetting defaults.

The only other option for using the non-default browser after you have one associated is to long-click the URL and then manually locate the browser you want to use in the Share menu. That is cumbersome AF. The present menu offered when a non-default browser is specified is much better, IMO.