Photos - syncing between phone and computer?

I am trying to figure out if there is a way to still have all new photos taken on my iPhone automatically upload to my Photos library on my Mac desktop and store in the Cloud without having every single photo in Photos also be on my phone. I would LOVE to do this automatically somehow without having to delete 27k photos individually from my phone. Also, it seems like half the information I've read says that if I delete it from my phone with the sync feature on then I'm also deleting it from my computer, is that correct? This was so much easier when they were totally separate and nothing I did on my phone affected what was on my desktop. Is the easiest solution to just turn off these features entirely and manually importing new photos by connecting the phone to the desktop regularly?

Sorry if this question doesn't make a ton of sense. I have been using Apple products for my entire life but typically because they were easier to figure out for someone who isn't very tech savvy. Not sure that's true anymore...