VLAN - do all switches have to be managed?

Hi, sorry for this n00b question, but I am planning to switch my router to an OpenWRT model to be able to use - among other things - VLANs. To segregate some clients, e.g. certain smart home components. I already have a 8-port simple 2.5 GbE switch and was considering adding a second one - maybe a managed one. Now I got a bit confused about VLANs. Is it enough to have a VLAN-capable router to use the feature or does every switch in the network have to be VLAN-capable? What would the limitations be if I used "mixed" equipment with one managed and one unmanaged switch?