STP Unmanaged Switch - Would a loop occur?

In the case of either of these two networks, https://imgur.com/a/sOQ7v4B where STP is enabled on the management switches and STP is not enabled on the Unmanaged switch does spanning tree still block the redundant connections in both network A and network B?

Since STP is not a feature of the unmanaged switch in my situation I was curious if STP convergence would take place or if a loop would occur?

If a loop would occur could we use something like BPDU guard on one of the downlinks to the unmanaged switch to potentially block on of the uplinks?