"I don't know where Cap got a shield to give Sam since Thanos destroyed his..." implies a plot hole - that Cap is giving Sam the shield that was destroyed earlier.
No where in OPs question do they differentiate between when Cap got the shield or where he got the shield. Only that the shield was broken and now he's giving it to Sam. Which isn't the case, it's a different shield from the past that's not an exact duplicate for unknown reasons. Any guesses more specific than that would be conjecture.
Here's a link to a basic reading comprehension workbook on Amazon that you might find useful to avoid looking like a fucking dipshit in the future. It is for first graders so you might find it a little challenging at first but you'll get the hang of it.