As a seasoned solo traveler and big fan of lounge dining, your options are quite varied. Since that means you 're not on a Dining Plan, it opens up some other options. Bluezoo and Il Mulino (Swan/Dolphin) have great food/service in their lounges, with more choices and generally better food than the Disney hotels.
Between Citricos and CA Grill lounge, I give an overall edge to CG, especially since there is the added benefit of fireworks viewing (and you can return later to watch the show if you dine earlier in the evening). You need to show your dinner receipt to regain access. Just know that their lounge can be a madhouse that's not in keeping with the pricetag. Citricos is fine and less frantic, but it just feels like "hotel food," (albeit good hotel food) with a relatively limited menu. I have had excellent service on every visit, however.
Morimoto Asia is an outstanding solo choice, either in the lounge, sushi bar, or the knock-your-socks-off omakase experience (pre-booking/deposit required). I'm also a big fan of the counter "cooking place" at Jiko. I like to build a multicourse meal with just non-entree courses and paired wines. Two or three selections from apps/soup/salad and dessert makes for a perfect leisurely meal with nice interaction from the staff. I believe you need to reserve a spot at the chef's counter directly (not through the app/website).
I also find Tiffins at AK to be a generally good solo dining place. Although the menu seems to have been dumbed down a bit, they have kept some of the best dishes. It is also quite serene for in-park dining. Unless, of course, there happens to be a nightmare family in the house (sadly, a risk almost anywhere in WDW).