Can I sync two macs to iCloud Photos?

Hi. I have bought a new MacBook Pro, but I still use the old one.

I was searching for some pictures, and then I realized my Apple devices were synced, but not really.

When I go to ID Apple in all devices, I can see everything is supposed to be synced because it is enabled. But I cannot access any photo from or file from the old computer 💻

I have been trying to fix this for hours; I have enough storage space available and the old one says it loading to the cloud, but the loading bar and quantity never move.

Should I drop iCloud and use another cloud instead? It does not make sense to pay for something that does not work...

Thank you!!!