How do I remove unwanted photos from MacBook and stop them from reloading?

As long as you have iCloud Photos enabled on the Mac, it will synchronize its main Photos library against iCloud, and therefore against any other device that has iCloud Photos turned on for the same Apple ID.

It is possible to have multiple Photos libraries on a Mac, in which case at most one can be synchronized against iCloud, and the others are strictly local.

I don't know how to explain the system library taking up 127 GB on your Mac and only 10.7 GB in iCloud. iCloud Photos always keeps any full-size photos and videos that it has gotten the chance to upload in iCloud …

… unless, perhaps, you are out of iCloud storage space, and synchronization stopped for that reason. If that was what was going on, that would indicate that most of your photos exist only on your Mac, and that were something bad t happen to your Mac, the photos would be gone (unless they were in local backups).

If it was me, my inclination would be to

• Exit Photos.
• Copy the entire Photos library (Pictures > Photos Library.photoslibrary) to a couple of spare external drives, to archive it.
• Turn off iCloud Photos – on the Mac only.
• Exit Photos.
• Move the entire Photos library to the Trash and empty the Trash. (Alternately: select all of the pictures from within Photos, delete them, then go into the Recently Deleted album and select and delete them again.). This step will permanently delete the copies on the internal drive.

I would be very careful about doing things in the right order, since my priority would be to preserve the photos being archived, and to leave any photos already on the phone untouched.

If you wanted to access the archived photos at a later date, you could hold down the Option key while launching Photos, and select an archived library on an external drive. The photos would remain on that drive; they wouldn't migrate back to take up space on the internal one.

First you need to decide what you want. You've told us what you don't want, but you haven't said what you do want. Do you want two Photos Libraries, one personal and one business? Do you want all the personal pictures off the Mac completely? Do you have another device that you want to keep connected to iCloud? Do you want to keep all the pictures at iCloud, or do you want some to be deleted from iCloud?

I also don't understand how the "performance is affected by all these Photos." In what way?

Can you tell us what percentage of your storage on your Mac is free? Can you tell us how much storage is used and free at iCloud.com?

Ae you using iCloud.Drive?

I would recommend using iCloud Photos to help safeguard the photos on the phone even if no other devices are synchronized to iCloud Photos.

But what is the current status of the MBP- where you say you don’t want any photos? Is it synchronized to iCloud Photos? To Google Photos? to anything else?