iCloud Photos to External HardDrive

If I backup my iCloud photos onto an external drive so I can clear up some cloud space,

Backing up will not save you cloud space. A back up is a copy of data, on separate media. If you want to remove items from the iCloud Photo Library you would need to remove them from the System Library - which you can do by exporting, and moving them to the external - but this would not be a back up, as you will only have one copy of the data.

will I lose the photos on my devices?

If items are removed from the System library they are liable to be removed from the iCloud Photo Library, and from any devices that sync with it.

basically yes unless the photo was originally taken on that device. Icloud allows sharing of those photos to your other devices. Either way back up on a thumb drive or external hard drive for recovery because icloud is not safe storage device, in my opinion.

I would point out that Apple advise against using thumb drives and flash drives as permanent storage. Just not robust enough.

I find it works for me and is safer never had problem. Apple just wants to sell you cloud space.

thats all. I feel better with files locally stored on media I control not a corporation. To much is moving to cyber space and i don’t like my data there.

Apple don't make external hard drives or SSDs which are more robust than flash drives. So it's difficult to argue that they "just want to sell you cloud space". Cloud is only one option, and among the other's flash drives are less reliable in the long term. No need to assume the worst of everyone every time. As for

I find it works for me and is safer never had problem.

That sentence is missing two word: so far. Every form of storage is liable to fail at some point, some more than others. That's why backing up is important.

True. I’ve have had my share of minor glitches. What works for me may not work for others. I have a sold state back drive for backup and use cd’s for minor things and thumb drives for others. So far the down side i’ve seen with apple is lack of customization and user options. Thats why i’m thinking of going back to windows. Windows drove crazy but at least i felt i had control over my data.

So far the down side i’ve seen with apple is lack of customization and user options.

What do you feel you are missing? I'm no expert on Windows but I do believe that you can achiever almost all the same things on both systems, but may require different approaches to get there.

😆😆 I work on window system and own a iMac so I feel frazzled with both for different reason. They are starkly different in there GUI, not to mention very different in the terminal command line structure. I worked on unix mainframe once along time ago. Google changed everything with android and chrome. Basiclly I don’t trust any of these big tech giants. I feel they’ve taken away control of your system for their benefit not the users.

You can move some photos out of library into another file for safe keeping but i use a thumb drive and keep them there in separate folder

Absent a specific query I'll leave you to your ruminations.