iPhone rejects calls on Do Not Disturb instead of silencing the ringer

When I use the Do Not Disturb feature on Focus in my iPhone 12 mini, it rejects the calls of my callers and they hear the busy tone. Instead, I want the calls to be silenced from all callers except the Favourites I have selected in contacts. So, using the mute button at the side will silence the calls of all callers while I want the system to ring my iPhone for my Favourites contacts but no ringer without rejecting the calls for my other contacts. Is this achievable on iPhone by any means?

P.S.:

I know that, by design, Do Not Disturb is supposed to send the calls to Voicemail but here in India Voicemail is supported only for Post-paid subscribers and not for Pre-paid subscribers. So, activating Voicemail is not possible for me right now.

Also a similar question was asked by another user in India but it wasn't answered properly. The link is below:

Do Not Disturb... Reject calls instead of… - Apple Support ...Official Apple Support Community › thread