I think for Szeth, Nightblood also may have access to Szeth’s Connections to lashings in his Spiritweb, giving him a ‘roadmap’ to reconnect them.
I think Nightblood can not grant access to surges Unless they had had access previously. A bad analogy could be that Nightblood can not create a door to surges but can unlock an existing door that was locked to surges.
Nightblood was terrifying and OP before WAT, I think if they could grant surges too that could be world breaking.
I can’t see Brandon allowing something quite that uncontrollable. Would break most of the systems I can imagine
Wouldn’t be able to do so in one sitting. Nightblood would saturate, have to stop/slumber then restart. Ie when Rayse was consumed