Hi guys, I apologize in advance if the questions I am going to ask are potentially stupid, but I am just getting into the world of sound systems these days.

First question: I have a TV that supports Dolby Digital Plus and also Dolby Atmos, which in turn relies on the same DD Plus. Does the term “supports” simply mean that the TV can output these audio signals to external devices (such as Soundbars or AV receivers), or does it also mean that the TV also outputs them through the internal speakers? Or will these still always output a PCM 2.0 signal? Example: I am playing a game on ps5 that supports the Dolby Digital plus format . Does this format also come out of the TV speakers or can it only be output to external devices?

Second question: can a 2.1-type system, in addition to supporting classic PCM, also support Dolby Digital and Dolby Digital Plus signals, in theory? Or are they only compatible with systems, respectively, 5.1 for DD and 7.1 for DD Plus?

Third question: if the answer to the second question is yes, it would still not make sense to use a DD or DD+ signal on a 2.1 system, since they are compressed formats, so they lose quality compared to PCM. Right?

Fourth question: with the advent of eARC, it doesn’t even make sense now to exploit a Dolby Digital and Dolby Digital + signal on 5.1 and 7.1 systems, because eARC allows you to get a multichannel PCM, which is of higher quality. Maybe it only makes sense to use Dolby Digital + because it also carries Atmos, so you can exploit it as an alternative to PCM to get a 3D effect that PCM does not give. All correct?