I've been thinking a bit and I'm still wondering why we're naming genres about pre-existing games or between two existing franchises?
Especially when Souls-like are still fundamentally Action RPG (with a stamina bar management) and Castlevania stopped being a Metroidvania for a decade at least.
I think that they could fade out like the term Doom-like/Quake-like and even GTA-like to a lesser extent. Crime Simulation sounds better.
Maybe Platformer/Exploration would work for the Metroidvania genre? As for SoulBorne/Soulslike ARPG with stamina or dark souls influenced would be more apt.
Personally, the purpose of game genres is to help developers explain in simple terms what their games are about, what you as a player will be doing in that game.
In this sense, genres named after games are the most useful and well-defined.
Like, what is action? What is adventure? Any game can contain action or adventure, but that doesn't help you understand what the game is about.
What is racing? What is fighting? What is pinball? Now, these are based on "pre-existing games" (sports are games after all), so I can imagine games in these genres following similar rules to the sports they are based on, and therefore have a good idea of what to expect.
Metroidvania, Souls-like and Rogue-like follow the same philosophy, a game that is part of these genres basically says that the game follows a similar set of rules, it gives a good idea of how these games work, the difference is that instead of being based on a real world game, they are based on an existing video game.
Let's take Metroidvania as an example...
Both Metroid and Castlevania SoTN (which was nicknamed Metroidvania) were based on the classic 2D Zeldas, but people used to call them RPGs because of their top-down view and the series is also not consistent in its rules with the 2D Zeldas being the only "by the book" Metroidvanias, so calling the genre Metroidvania to define its ruleset around Super Metroid and SoTN is fine (that said, among friends I call them Zeldroidvanias).
Calling a metroidvania a platformer/exploration game says nothing about the rules of the genre.
SoTN, despite having platforming, falling doesn't damage or kill you, so you could say that having platforming skills isn't critical for it (the PS2 games barely have any platforming, for example).
Resident Evil has a lot of "metroidvania like exploration", but it's not a Metroidvania, why?
One of the rules of Metroidvania is to have the "key-lock" mechanic, where the key is part of your combat or movement moveset and the lock is an obstacle that can be overcome somehow by "this key".
This is what makes things like sequence breaking possible, because you can often overcome the obstacle in other ways, like instead of getting the "hi-jump boots", you can use the wall jump to get over the same obstacle sooner.
Resident Evil is almost a Metroidvania, but since it uses actual keys and locks, it doesn't qualify.
Like, you can only open the red door with the red keycard, and the keycard doesn't expand your movement or combat options in any way. You can turn Resident Evil into a Metroidvania simply by replacing all the key-locks for things like a rocket launcher to blow up cracked walls, Molotov cocktails to burn away spider webs, "mechanical leg armor" to run faster and get past traps, etc...