Yes, the attached diagram refers to a 2P2T relay. I have found the following description from
https://hackaday.com/2017/09/26/an-introduction-to-solid-state-relays/:
Due to the internal construction of SSRs, they are only available in a single-pole, single throw (SPST) configuration. Single pole means that it can only control a single circuit, and single throw means that there are only two positions the switch can be in (one on, and one off state). Mechanical relays do not have this limitation and are available with multiple poles and throws.
This statement confirms my suspect somehow. I think this limit results from the power semiconductor characteristics.