Questions about the AT&T and Discovery Spinoff into Warner BrothersDiscovery

So At&T and Discovery are spinning off into a new company with a new stock, WBD. As I've read DISCA/K holders will get 1 share per share, T holders will get .24 shares per share.

I'm unsure what typically happens after these spinoffs. It is assumed that WBD will trade at whatever DISCK is trading at now (around $28) and that T will tank give or take 25% once they get their shares? Because someone holding 100 T shares will essentially be getting $700 dollars in new shares, so that value must be factored into the current price.

Can you use this opportunity tax loss harvest or is the spinoff a taxable event? I.E. Buy T now and sell when it tanks for a loss but still essentially retain the original value by holding the WBD shares.

I've read the transaction hasn't closed so I'm guessing the ex-date hasn't passed yet.