There is an alternative to grindiness, although its not overly popular because it's slower, but you can cap a third life toon doing every quest on elite once, only needing to either grind out a few slayers or second quest runs at levels 14 and 17 becuase in the teen quest levels the list is small. I know, because I did it as an experiment to see. Each quest once and on to the next was fun and didn't feel grindy to me at all beyond the unescapable fact that I've been playing this game for four years and there are literally no quests or raids I have not done multiple times. And I used no xp potions on that life, just the 10% lesser spell tome I got on all my toons from the motu preorder, the voice, and the ship 5% buff of course. Basically I did it because someone once pmd me to the shut the hell up when I disagreed with him that you HAD to grind the huge xp quests over and over to level a 3rd life tr in a thread. I don't get mad, I prove my point. Next life I want to try doing hard and elite runs of every quest that does NOT have an epic version and see if I can cap without a ridiculous amount of sre's and still have first time bonuses on the epics. I succesfully did second life elite one and done skipping all quests with an epic, so I think an e/h run for a third life should work.
You don't have to try it of course, I just raise it as an alternative, especially since I believe you mentioned you are vip and therefore have access to all the quests. And if there are ones you really hate you can skip them with a few reruns of ones you like, it's a flexible plan. Sometimes the solution is how you approach the game. I like experimenting and dislike grinding quests, so I made an alternative option. Perhaps some form of permadeath or iron man variant where you run a toon with only what you pull, no auction house and no repairing, might bring some fun back into it for you.