Zoro shouldn't let any swords break anymore and then be rewarded for that.
Mihawk already said Zoro should not let any blades break under his usage, he should be ashamed if any sword he uses after learning Haki gets nicked at all.
It's a matter of respect and honor for a Samurai to protect his blades and use them with the best of his abillities, without breaking it.
Enma might look like it's overshadowing Zoro and his other blades right now, but by the end of the Wano Arc, Zoro is the one who's going to be respected and receive the praise from the people of Wano and probably from Kaido and Big Mom themselves. Zoro will be able to emit the same type of haki from the other blades and they will all feel the same.
Besides that, Wado is at the same grade of Enma right now and will become one of the Supreme Grades when it turns into a Black Blade, probably after he does it with Enma. We all know there's a chance Zoro might trade Sandai Kitetsu for Nidai / Shodai Kitetsu by the end of the series, and that blade would also become a Supreme Grade if turned into a Black Blade.
So yeah, i think Zoro should keep Enma, and it will stop overshadowing Zoro and the other swords by the end of the arc.
Not only that, i want Zoro to keep Enma for an epilogue after the end, imagine Zoro becoming the WSS by the end of the series and then on the epilogue we see old Zoro in Wano relaxing and drinking, but also bored like Mihawk because there's no swordsman on his level to fight anymore. Then we see older Momonosuke aproach him with his Ame no Habakiri and challenge Zoro for his title of WSS and to get Enma back, his father's old sword, to me that would an awesome epilogue scene for Zoro, Momonosuke and Wano.