Blueprints eat only tiniest amount of storage. Like 50-100 blueprints for one single photo. Also worlds themselves eat the same little as blueprint, but each new quicksave eats more, almost like new world.
Thus instead of deleting it, you can simply move it to another folder, so it would not get in the way. For example i have near 300 blueprints in extra folder, but in game menu i have only 10-20 blueprints at a time, only those which i am interested in at this current moment.
Also all worlds and quicksaves have the same repeating data inside it. So you can make 7z or advanced rar archive of entire 100 worlds with 2000 quicksaves in it and this archive file will be the size of several worlds with several quicksaves. And the same with blueprints. You can add +1000 blueprints to this archive and it will become just +1 or +2 bluprints bigger in size.
And also you can just upload your copy of all worlds and blueprints to somewhere in internet, at goodle drive, microsoft drive, apple account cloud storage space, and so on.
So there is no need to delete anything, it just takes very tiny amount of storage space.