Batman: Last Knight on Earth is a love song, an idealistic cap, and love letter between Snyder and his team (Scott Snyder, Greg Capullo, Jonathan Glapion, and FCO Plascencia) and the idea of Batman. It is not the end of Scott Snyder working with the character Batman as his work on Justice League continues to utilize the character and he will have a role in the upcoming sequel to Metal: Death Metal, but this is the thematic and ideal cap to the writing he did for the character.
Snyder has said in past interviews that if he were to end Batman it'd be him and the Joker going down fighting, much like you saw in Endgame. Perhaps that has changed, maybe this is his definitive end as he's still using the idea of Batman cloning himself and while I was not fond of the idea at first I've grown on the concept as my world view has expanded and my readings of Batman have expanded. Superheroes have been around for a very longtime and exist in every possible medium so they become ideas and each writer, artist, colorist, inker are all presenting their idea of the Bat, of the Spider, of Wonder Woman, Captain Marvel, etc. Because these characters will outlast us and grow beyond us.
You can take that a few ways, you can see that as corporations peddling these marketable and heavily merchandised icons down our throat for decades, or and the way I like to see it when I'm optimistic enough to think so is that these ideas inspire and help us through whatever time we may be having. Batman has been there for me in the best and worst of times and can be an inspiring symbol no matter what. Some people would say it's foolish to be inspired by a fictional character or fiction at all which I guess makes me foolish, but I will always be foolish then.
Getting back to it Batman is an idea and Last Knight on Earth is Snyders last paragraph in a long essay on what Batman is. It is big, pretty, bombastic, and telling of what the team feels for Batman.
The story will not work for everyone, nor do I think it should be read on it's own because it is an ending after all. Of course you could and I think it'd still be pretty damn fun.
The pencils are the finest I viewed last year, Capullo is a master of his craft yet he learns from every story and his style is now iconic with the Bat. FCO colors the art in a way no one else can, the color palette is vast in this work and makes it all the better for the skill at hand. Jonathan Glapion inks the piece and makes the pencils even better. Each part so essential to bring this to light, it is a finely crafted standout that I don't think any fan of the previous run or Batman should miss.
This is the thesis statement of Snyder and his team and it was a wild ride.