If u go with a 2bay you should go with 10tb or more. You wont be able to expand. SHR-2 is not worth it in a 4bay imo. Shr is the way to go, its optimized for the NAS and for expanding later. Maybe check some prizes to see what makes sense.

Yes but theyre cheaper than ironwolf.

On a tight budget id go with 2. A even cheaper case and drives that can be used in a NAS in the future.

I have iron wolf 3TB in my NAS. But seeing they only increased in price over the last months i reconsidered. I just bought Exos E 8TB because theyre quite a bit cheaper and should perform equally. I have to install them yet.