No, the DMA has nothing to do with RCS, at least not directly.
Yes, WhatsApp and Facebook Messenger were initially just XMPP servers, but have since had proprietary expansions.
In the context of the DMA both of them will be forced to make interoperability with other third-party messengers possible, since Meta has been designated a "gatekeeper" under the new regulation. Meta has announced they plan on doing so via an implementation of the Signal protocol.
Not with Signal messenger, the company running it hasn't been designated as a gatekeeper under the DMA rules. You can see which services will be affected on the Wiki page (only WhatsApp and Facebook Messenger currently).
Right so WhatsApp and messenger are gatekeepers and they must allow interoperation with who anyone who wants to ie me running my own signal instance? They also need to interoperate with signal hence if a works with b and c works with a why wouldn't b work with c? Cos if thats hoe it works or if im not allowed to interoperate with WhatsApp or messenger in the first place then this juat seems like its handing the monopoly away from the companies to the government and giving the people fuck all.
Right so WhatsApp and messenger are gatekeepers and they must allow interoperation with who anyone who wants to ie me running my own signal instance?
There are several stipulations on interoperability in the new regulation (Ctrl+F "interop"). To my understanding it is stipulated that they have to make interoperability possible for certain third parties, but how to go about this is not exactly specified on a technical level - meaning the specific way to implement this is left to the gatekeeper. So your Signal server may or may not be able to depending on how exactly they go about this.
They also need to interoperate with signal hence if a works with b and c works with a why wouldn’t b work with c?
No they need to enable interoperability period. Says nothing about Signal (the software) per se. Meta has announced they plan on implementing it based on the Signal protocol (not Signal messenger software, not Signal server software).
Cos if thats hoe it works or if im not allowed to interoperate with WhatsApp or messenger in the first place then this juat seems like its handing the monopoly away from the companies to the government and giving the people fuck all.
To my knowledge the aim of the regulation is exactly that, to allow anybody interoperability with these "core platform services". The status quo is that the regulations has been announced by the EU, it has gone into effect, and Meta has announced how they will implement interoperability to comply. Once the implementation is available and then found lacking in regard to the regulation it would be up to the affected third party to sue Meta over it.