Are you looking specifically for gels or would you consider drink mix? I use a custom mix from Infinit Nutrition. I don’t think it is as expensive as Maurten but I honestly haven’t done a side-by-side comparison. They have many pre-made formulas but they’ll also give a free phone consult to setup a custom mix - price is nearly the same ($60 / 25 servings). (I only use it for 2+ hour interval workouts, though. I use watered-down Gatorade, gels, and Precision Hydration for shorter duration and / or less intense rides.)
My custom mix is below and has 72g of total carbs. Mine was setup for a Gran Fondo / Century, and I’m a medium-heavy sweater with a medium-high amount of salt loss. It worked perfectly - I didn’t need any other nutrition or salt during the 5-hour event.
https://www.infinitnutrition.us/the-infinit-difference/product-comparison.html
I’m quite pleased with the product and happy to go into more detail if you’d like.