Whether you surrender or play through it, you’re still bound to get the same RR deduction on the loss.

This game does not reward you at all for someone afking on your team no matter if you decide to play through it instead of surrendering.

I don’t understand why even play a 4v5 if you’re most likely to lose and still lose the same amount of RR. You’re better off cutting your losses and surrending and starting a new game. Yes there are rare occasions where you win a 4v5 but it’s not the case in most scenarios, especially in Silver elo.