No they support it because of Azure Cloud and DotNet applications.

That is exactly what I said.

But in some point in time, epic will probably deliver a Linux client and then Valve will probably be forced to make it easier to get the launcher,

Epic might* make a linux client if they see a reason to. But is very unlikely valve will be forced to adopt the epic games launcher into their "gaming mode" that is unrealistic. There is 10000x more monopolies to crack down on before anyone takes a look at the tiny handheld linux gaming market.

Nothing you've said provides a reason why Playtron entering the linux gaming market is anything but a positive for linux as a whole. I feel like you think I am attacking valve by talking about their monopoly. I assure you I am not, I like valve and I own a steamdeck. The idea of a gaming app that easily allows users to run games from all platforms equally aligns more with the linux ethos more than the only option being the Steam gaming mode store front and everything else must be added as a non steam game.

This argument is like saying the switch needs to include steam os software because they're both handheld gaming devices

Also, as I said previously, it's incredibly easy to install things on the steam deck, I don't think there is any way they could make it easier because you would just install it like any other Linux program

You either don't own a deck or don't know how to use desktop mode