NextCloud 13.0.4 - huge preview folder size (300GB)


Our NC server reach the maximum storage space and hangs, i noticed that the preview folder: /var/www/html/nextcloud/data//appdataocy3… (etc)/preview/ has reached 300GB (more than half of total storage).
First question: is it possible to delete the content of that folder (to solve the problem right now) without impact to NC functionality?
Second question: is there a method to limit the total amount of data storable in that folder so the it does not so that don’t overcome a predetermined limit ?