This question resolves to YES if I can both receive and send:

• Text messages

• Voice messages

• Pictures

Between accounts on WhatsApp and Signal on or before Feb 1st without having to sign up to a third party bridging service.

For context, the EU's Digital Markets Act will go into effect September or October of this year, as soon as the necessary institutions approve.
It requires basic interoperability between Messaging Services, 3 months after they have been asked to implement it.