Hello @Maël_Shanti and @INSIDE, and welcome!
Yes, Discourse is a great replacement for BuddyPress. I’ve worked with many sites that have used BuddyPress, then moved to Discourse, and been glad they did.
I understand what you’re envisaging, however there will never be a complete version of Discourse working within Wordpress itself. This question gets asked quite a lot so let me try an analogy here to illustrate why this is the case. Imagine there are two buildings, one is residential and one is an office.
Now, in modern town planning and the modern workplace there are quite a few different ways that you can bring the home into the office and vice-versa, ranging from home offices, co-working/living, mixed-used buildings and others.
Imagine Wordpress is the residential building and Discourse is the office building. In this analogy the WP Discourse plugin is essentially a co-working space inside of a residential building. It’s a place you can go to get an office environment close to home. You can review some work there and perhaps hold some meetings. For most of your work though, you’ll want to go over to the main office building where you have all of your teammates, and all of the resources you need.
As you may also know, the reality is that the nature of residential and office buildings are such that trying to truly combine them at scale will always be attractive in theory, and there will always be folks to whom that idea appeals on paper, however the practical, technical and cultural realities of such a fully fledged combination are why, in practice, we have separate residential and office buildings, and why, in a significant majority of cases, that makes sense.