Problem solved. It was a DHCP conflict. But I didn't thought about it because even now it still says there is no internet connection. But there is... however. Everything works and it's ridiculous...

This is what chatGPT says :-) : Yes, you can connect a TP-Link EAP (such as EAP225 or EAP245, which use the AP653 chipset) to an OC200 Omada Cloud Controller without necessarily using a TP-Link...

I just bought 2xAP and 1xOC200. I thought I don't need a router like ER-605. Is there a way without? I don't get it. If I try to connect the APs via Cloud Controller it says "Too many PRECONFIGURED...