Couldn't tell you a Grenache versus Merlot because I haven't reached whatever baseline of recognition is required.
That's been a very slow 20 year journey. I'm not detecting hints of blueberry or oak, that feels like pantomime still.
Grenache - I tyically drink Spanish Garnacha - has a crunchy berry profile in a young early drinking wine, but can get more interesting in pricier examples from Priorat etc.
Grenache + Syrah (aka Shiraz) + Mourvèdre (GSM) is the southern Rhone blend, and is typically very high alcohol and quite opulent. I'm not much of a fan though.
Mourvedre is fantastic stuff when done well. Mourvedre reminds me of Carignan, both make savoury / meaty wines. Domaine Tempier Bandol is a Mourvèdre-dominant blend and is absolutely delicious, my favourite example of it.
Oak is a big part of really good wine. American oak, French oak and unoaked all produce very different wines. Typical Rioja has heavy American oak flavours, while e.g. red Burgundy typically has pronounced French oak.
There is a very limited number of things an individual can get deeply into.
Then proceeds to speak in completely alien language, thank you for proving my point :)
I am saying learning such language takes years of practice, and such a hobby is only available to (relatively) few.