I have been RPing my Dark Ranger for almost 10 years now, started off on a private server before finally making the jump to retail during WoD. Dark Ranger RP has always been a subject of scrutinisation. Mostly because of the edge factor but also because they are rather OP and most people tend to just RP them in an awful manner (trust me I started like that as well).
What I noticed, however, was that the amount of Dark Ranger RPers has actually INCREASED since the departure of Sylvanas. Why? I cannot tell. Probably because now they are the dying legacy of something which gives them a “cool factor”. But most characters I see are just people half-arsing. You know, the type that makes a TRP for a Dark Ranger, barely fill in said TRP, log in maybe for a month and then disappear.
Right now, the environment to RP them is more limited than ever. Most guilds/people will either flat-out ignore you or treat you like dirt (as they usually are). You are either a loyalist, and therefore an enemy of the Horde, or remained part of the Horde, which leaves you in the position of being barely tolerated. I haven’t been able to even get into a guild with my Dark Ranger ever since BfA (at least not a guild I want to be part of without mentioning names here).
So TLDR, there is RP, but it is very very limited.