You will have to get it individually
Get custom chess puzzles in bulk

Is it possible to get chess.com custom puzzles in bulk? I only need 300 puzzles as a png.
You could just do 300 custom puzzles and copy the png for each, since you have diamond, but that would take a while

If you know some coding you should be able to write a script which generates URLs and does screen grabs.

Just download the lichess puzzle database and use code to extract 300 of the puzzles and turn them into pngs
https://database.lichess.org/#puzzles
Is it possible to get chess.com custom puzzles in bulk? I only need 300 puzzles as a png.