If you want to do fantasy adventuring, no matter what you use, it will end up being compared to D&D.
Then the question is: how do your players feel about (your group’s uniquely tailored version of) D&D.
That said, the argument “I am the GM and I am struggling, please let’s use a different set of rules to play our favourite game together” should suffice.
Don’t make it about the games (even though for you it is all about the game 
), don’t make it a matter of comparison, etc.
Be honest, forward and forthcoming, but make it about you as a person and as a friend, and your need to try doing the same thing in a somewhat different way, and would they like to support you in this?
Very often good people become grognards out of some misplaced brand-identity-loyalty hiccup.
Avoid this, and you’ll have a much better chance of them embracing a different game, whatever it might be.
That said, what are you looking for in a game? 
Dungeon World is a very different beast from D&D, but at the same time it’s a very D&D-ish game itself.
It requires the GM to have a strong grip on both the PbtA framework, without reeeally supporting them too much in that task. It has solid mechanics, but with a bunch of critical grey areas that make it relatively easy to end up playing it like you would D&D, but not really, but different, but the same.
Maybe it’s exactly what you need: a D&D with a more narrative framework.
Other PbtA are much more different from ye olde traditional GM-led rpg, even though they still have a strong GM role at the table. They will fight you more if you play them like D&D, which is generally a good thing, because you either play them correctly, or you soon realize they are not your cup of tea.
But most still rely on GM and Players having a solid PbtA background.
You can learn by doing. They do work. But to grok them can take time and effort that some don’t expect. This can be a jarring experience, and could thus mess with your (and your players) acceptance of this new thing you are trying.
Some just love it immediately though.
Some fervently hate it, too.
You need to try
In this context, Fantasy World was designed to introduce people to fantasy adventuring in a definitely non-d&d-ish way.
You explore, you fight, you do all the cool things one could expect, and more… but the focus is on “dramatic” narrative. Character motivations, hard choices, personal stakes. The good stuff of fantasy novels and movies and TV series.
Violence is meaningful and scary and never trivial. I lost count of the times when the Players geared up for a “seek and destroy” kind of situation, and them they ended up doing everything in their PC’s power to avoid actual violence. Either because the game treats everything and everyone like “people”, which often is enough to have Players consider social or crafty alternatives to violence as more interesting, fun and often more viable. Or because combat can be both be effective but also extremely dangerous, some even call it Old School -like, and thus Players quickly learn than blindly charging or being needlessly violent is often not a smart choice.
It is also designed to be as n00b friendly as possible: everything strives to be clear, unambiguous, easy to use. This game really teaches you how to play this game.
This is a boon for both people new to RPGs in general, but also for veterans of traditional games (such as D&D) that are new to PbtA games.
Some hate this approach 
Many are finding it quite refreshing and helpful 
So again, depending on your group’s habits and expectations it might be more or less welcome.
Another title to consider, is Blades in the Dark.
In a way it is even more D&D-ish than DW… relying even more on GM’s spot decisions, on extensive prep, on crunchy bits and options.
But it does so in a smart way, offering good tools and a decent framework to use them in.
And the “fantasy heist” setting is just too cool to ignore 
Too much work for my personal taste. But it’s another option you might want to look into.
