I have X number of shares and I’ve applied for Y more apart from my eligible 1 entitlement. In this case, will I actually be considered for additional shares? I’ve paid the initial amount to RTA. If not eligible for additional shares will they refund to my registered bank account?

Yes, you will be considered for additional shares (over and above your entitlement), but their allotment is not guaranteed and depends entirely on the issue's subscription level and the company's allotment policy. The excess application money will be refunded to your registered bank account if the shares are not allotted to you