If there is enough storage on my computer will all my photos stay on there if I delete them from icloud

No those photos will be deleted into recently deleted album and only stay for thirty days , but it will be erased permanently from server if you don't recover them Delete and recover photos and videos on iCloud.com - Apple Support

If you sync with iCloud, any changes that you make on any connected device or at iCloud.com will reflect everywhere. Deleting from iCloud will also delete from your photo library on your Mac.