Current plan is to ski on the Sun/Mon at the end of the trip "somewhere else". Of course that will be either 3 or 4 of us doing that instead of the whole group (similar to how 4 of us added Silverton to end of last years group trip). I'm currently pushing for that sub-set to hold off on making any hard plans until we are at least much closer to the trip if not even until we are about to land (eg ~1 week in advance).
Val d'Isere/Tignes is the obvious choice. With only two days you might want to make the first one guided.
I concur with Tony; Val d'Isere/Tignes is the obvious choice - scale, proximate location, prominent off-piste zones (entrance finding can be tricky), snowfall, and snow preservation. The resort is a series of valleys strung together with many freeride areas between the valleys - and, most importantly, the far end of eastern Val d'Isere or western Tignes (biggest vertical, fewest crowds, powder for days).
Alternatives:
Ste. Foy and
La Rosiere/La Thuile. Both are near the 3 Vallees, just a few minutes outside Bourg Ste. Maurice. Both are not too crowded and preserve powder (Note: I have not been to Ste. Foy, but it has the reputation of where 3V & Val/Tignes guides/instructors go on their day off), but the quality and scale of the terrain. However, La Rosiere supposedly gets the most snow in the valley since storms funnel into the San Bernardo pass and dump.
Chamonix. The Aiguille du Midi hits prime time in March/April with its intense north-side couloirs filled in - Cosmiques, Glacier Ronde, etc. (Note: I have never skied these). As well as routes (Grand Envers, etc) that join the traditional Vallee Blanche. However, conditions need to be just right. Also, you have skied Chamonix before. And the replacement cable car to the summit of Les Grand Montets is still under construction. So, a pass on Chamonix.
Courmayeur. Lots of N&E off-piste from the summit (Arp) at the resort proper and the Skyway. However, Courmayeur is lower in elevation (will affect snow by mid-March), and the Skyway faces south (best mid-winter). Although La Thuile/Rosiere is nearby, I would pass on it - especially compared to high altitude Val/Tignes.
Verbier. This a strong contender: high altitude, tons of steep terrain, and lots of obvious off-piste. You could likely follow/tag along with groups - some freeride terrain is skied so much that it gets safer and consolidated - like the Bowl at Aspen Highlands. It is Europe's best lift-served freeride terrain that maximizes vertical/ski time—few long traverses are required (except the back of Mont Fort). Coulior entrances can be a bit hidden: Banana, Stairway to Heaven, etc - but you can figure things out. The only downsides are a longer drive from 3 Vallees and staying in Verbier proper, which can be $$ pricey. It's relatively small, so food and lodging are costly. Other higher-end resorts are large enough to find something semi-reasonable (Zermatt, St. Moritz, Lech/St. Anton, Val d'Isere/Tignes) if you look and even make some phone calls.
La Grave/Alpe d'Huez/Les 2 Alpes. You have done that.
Andermatt/
Engelberg. Great areas, but too far away.
Some other potential choices: La Clusaz, Les Contamines, Flaine. They all have interesting expert zones, but smaller.
I purchased an Outside Magazine book years ago (~2000) with longer articles and descriptions about 'great' areas - with expert bent. For Europe, they picked: Chamonix, Val d'Isere/Tignes, Verbier, and St. Anton. More or less, I agree with this assessment/recommendation.
Unless someone in your group always wanted to ski Verbier, you should book for Val d'Isere/Tignes. Lodging for 2 nights can be tricky (sometimes there are minimums, maybe 3 nights?), so you likely need the lead time to find something. Tignes has more apartments and can be slightly less expensive. However, I prefer Val d'Isere due to its semi-historic village, freeride terrain areas, and familiarity with some restaurants/bars/on-mountain eateries/guide offices. Also, it has more trees for a storm day. It is less of a French experience since so many Brits go there.
Also, if you want a guide for a day, you need to book almost a month out to find someone. Generally, one side of the complex might be favored. Tignes side can get more snowfall, but The Retour d'est storms favor Val d'Isere (the east side that abuts Italy). Winds, too, can impact the alpine - they did on my trip in 2024. - Val d'Isere eastern faces were exposed to the Westerlies. Guides know what is good - and they all communicate with each other so they understand the unskied areas. It is easy to repeat anything on your own.
Even if there is no new snow, the terrain is vast - with some steeper areas to ski/couloirs. The Tignes Glacier is unique. Val d'Isere's Glacier is slightly less spectacular but offers tons of easy off-piste. Apres-ski starts on the hill at many locations at 2/3 pm...Ending at 5/6pm.
However, if I were in Geneva for a 2-day weekend, I would immediately go to Verbier since it's closer, and the freeride is more easily accessible. Also, it has yellow off-piste itineraries that are avalanche-controlled but otherwise are unmaintained. (Or Chamonix and/or Courmayeur).