RTSP usage

I started researching RSTP and my head practically exploded. I have a simple setup using SWoS. Using the CRS309-1G-8S+IN for SFP+ connectivity. I have the Ethernet port connected to an unmanaged switch which connects all my 1G devices and the firewall/router. I am not doing any bridging as I see it. Should I just disable RSTP or doesn’t it matter?

I assume that the only time you need to use RSTP on a port is when it is attached to another level 2 switch. Is that correct?

It is beneficial if you need redundant links between switches or to detect loops on the network. If neither of those apply to you - you can disable it.

There’s no harm in leaving it enabled, it simply protects your network from looping.