Superior doesn’t motivate
What do you do when your superior doesn’t motivate, favours other people more especially women? The guy is younger than me by 15 years.

You need to understand his motivation. it may be that he genuinely feels these people deserve his attention, and /or are worthy of promotion. Maybe he thinks they have more to offer than others.
Or maybe he thinks they need more help and encouragement than you do. Maybe he thinks you are older , more experienced, and wouldn’t benefit from his leadership and mentoring
All you can do is be the best person you can be, do the best at your job, go the extra mile, be above reproach.
It is always difficult to work for a younger, less experienced person than yourself, but it is also difficult for them to manage you.
Maybe he is more comfortable leading and motivating younger people, and feels that it would be impertinent or patronising to motivate you
If you think that is the case, perhaps you could try and develop an easier working relationship between the two of you by chatting to him as an equal, but be careful to respect his seniority.