Hello,

I'd like to cover a large restaurant with wireless signal, and their main request is, that the network would be the same, without changing between APs, now I wonder what would be the best way to it?
I have 4 RB951UI-2HnD that I plan to deploy, I did play a bit with WDS dynamic but it was kinda unstable, so I'm thinking to go as regular wireless repeater mode.

So looking for suggestions, or guides to cover it

You can do it with more AP use the same SSID, channel and WiFi password.
When you have 20% signal from the first AP then place there a new one which is connected with the switch.
So you have roaming
You can make a Mesh network

This sounds more like a hotspot style solution which utilizes a controler.

The issue you may have using multiple APs without a controler is that devices may try to stay connected to an AP as they move out of range causing bad performance on the AP.

If you use a system with a controler then the APs will move the devices between themselfs allowing the APs to maintain good performance and seamless connectivity for the clients.

Solutions which I have used that support these features are;
Cisco Meraki
Rukus Wireless
Ubiquiti UniFi

What if I set it to disconnect client on "Connect list" at -80 ?

I got it to work, but it takes a second or so to connect to new AP, is there a way for proper seamless connectivity, like being connected to both AP's at the same time before you disconnect, or it does not work like that due to wireless standard itself?