CRS326-24G-2S+RM only act as switch, without any other option, possible ?

Can it act as switch only, without routing, vlan ect ?.

Sure.
That’s how it default starts.
You only need to look at the IP address, rest of config default starts as a pure switch (because … that’s what it is !).

Look at IP adress?, you mean set on them IP in range of what router passes ?

Yes.
Surely your default subnet is not going to be 192.168.88.0/24, is it ?

Yes, alright, that i will config proper way.

Yes it can act as a router but the routing throughput is not the same as switching throughput.

Another option is the CRS326 is dual boot, so it can be configured to use SwitchOS. Makes a great fully managed switch.