Your not effectively changing that tile without causing more damage. Live with i as is until you tear it all out. Where the tile is installed will tell you how soon you need to rip it out.

The cure is worse than the disease. Live with it please.

That's an impact star crack. You could try to dribble some thinned out super glue in the cracks, just so dirt won't get in there. But that is part of your house's life story now. Until you renovate.

I was going to try those touch up glaze but super glue seems to be better. I'll try that. Thank you all !