Preface:
Been playing since just prior to Highlands being added to Conan Exiles. Early 2017.
Like many others have said Private Servers (PC Version…Not really available for consoles)…especially Role Play Centrist keeps players playing. No B.S. PvP is fun but in very limited (Role Played up to it) and Admin Monitored Event Form. Even if you don’t Role Play that much or perhaps not ‘RPd’ before. Meeting a few peeps and chatting while drinking and eating is intoxicating. Feeling your character come to life by YOUR hands is a really cool feeling…and not just controlling animations and hacking at harvesting s-h-i-t. I will say that a 5/10/20x Harvest and quick 60 and build your base in 1 weekend is a wild and fun experience…just do that in Single Player Mode to get your build kicks…it leaves the rest of the game very dull. There is a really fine balance to giving enough harvest and keeping things interesting. I have it figured out personally.
A very good Role Play Server will have a number of mods. There are a lot of common ones and then some more specialized ones. When searching try to stay with servers that have the more common/stable mods since they rarely change and when they do they rarely break s-h-i-t. Which in the end makes everyone happy.
Finding a server with a good Admin. This is hard and takes some time to find. What makes a great Admin is that they care for their server. They build RP/Trade hubs for players to use, they help players with things but never give unrewarding free things (like various building pieces not yet known), they keep the server clean of garbage and leftovers from players who left, and they play their own server as a player hand crafting everything. Usually they will not put up with any Player B.S. either which keeps griefers/stalkers out and keeps the mood enjoyable. Sometimes Admin duties/responsibilities SUCK…but have to be done…DAILY.
Lastly, Conan Exiles is a lonely game. Even on the Official PvP f–k fests 90% of the time is playing solo or with clan members when they are online at the same time. It is a lot of repetitive activities to keep your building stocks high enough when a Purge/War happens and your base gets wrecked. Start rebuilding! PvP is more like PvOfflineRaid and few actual good PvP exists…so in essence it can be very toxic. As stated as a Role Play server with a good Admin the toxic behavior is nullified which makes this game A LOT of fun.
This may be a sales pitch but my server is a good example of what to look for. I have everything listed and described on both the Conan Forums here and my Discord. Sure it is an Adult server but that ERP part is just a tool…can be used or not…it is there for players to be fully immersed in a world that actually has that as a main theme…and we can run around nude. You can find the details here…
I can recommend another solid RP server with good Admins but will not advertise it here in the forums.
At the end of the day YOU have to decide what you deem fun. End game can be just Mid-Game if the Private Server Admin(s) make the game challenging and fun. Losing thralls can be great fun if they are mauled/wiped by great dungeon romps. Train and armor up another! That is what End Game should mean…not just grinding for the sake of more GRIND. F–k that! Let’s have some brutally satisfying fun and laugh our a$$e$ off while teaming up and then reliving our fun by telling tales in chat while getting drunk.
That is FUN. 
Thanks for taking the time to read