An expandable 26" is probably your best bet with the current weight limit. I bought the biggest Rimowa Alu Multiwheeler they have before the weight limit came into effect. It is extremely lightweight compared to its volume, just around 6kg for 107l. But now it's almost always too big for regular use. Still practical though when I need to carry bulky or fragile stuff.

I also got an Eagle Creek ORV Super Trunk. Among the lightest soft-sided wheeled luggage for big volume, around 5kg for also about 107l. Obviously, since this duffle is soft-sided it won't take as much room if you don't pack as much, as opposed to a hard suitcase or rolling case. I like it a lot, I must say.