Concrete crack repair that works?

I can't get a clear answer, and I've tried various fillers on the market. Has anyone found something that works for a DIY repair?

These are both hairline and bigger ones. It's from moisture break down.

It's in a utility room, we don't need it to hold a car or forklift, and I'll coat them with epoxy after.

I thought epoxy works as a filler but then I see it doesn't work with natural movement, and I can't get a real sense of what brand of epoxy and type work in this situation.