I read this new manga, only one chapter though, where the MC successfully saves the other world and is sent back to the exact moment he was summoned. After returning, he spends the day with his friends and returns home late and out of habit uses light magic to light the room and is shocked that he can still use magic in this world.
It may be Kikanshita Yuusha no Gojitsudan. The Fate of the Returned Hero
The scene that you describe match the light novel End of chapter 2:
I climb the stairs and enter my room.
It is rather dark. Because my room is on the east side, it gets dark early in the evening.
As expected, I can’t see well, I use the magic "light" to light the lights.
I looked around my room, and entrust myself to the feeling of relief that I finally came back.
Put the backpack on the desk and fall to the bed.
A nostalgic smell of my room (it is not stink) with a smile.
Then I looked around the room all over again and settled.
I shouted spontaneously.
“Why magic still usable?!”
A light bulb created with the magic "light" floating near the ceiling of the room.
It matchs the Pages 51-52-53 of the First chapter.