The Steam Deck isn’t really a 1:1 replacement for a home console though, it really depends on your use case. It’s great at what it does, but not everyone is looking for a handheld. And if you’re into more demanding games the Deck also struggles to keep up. I love my Deck but if I had to choose between it and my desktop gaming PC I’d choose the desktop every time. Although it admittedly also was quite a bit more expensive.
Saying the Steam Deck is better value than a PlayStation isn’t really a meaningful statement without further qualification because they are two very different devices. That was kind of the point of my previous comment. If you don’t need any of the handheld features and just want to play on your TV then the PS5 is better value. If you want a handheld a PS5 is obviously completely useless and the Steam Deck is insanely good value.
Also, if you want to play current, demanding games, a €700 PS5 Pro surely is enough. Even a regular PS5 should do for now since the Pro isn’t even out yet. Personally I prefer a more powerful gaming PC, but if you just want to play some of the latest AAA games on your TV you don’t need to spend more than 700€ unless you have other specific requirements.