Defence in depth. Which of your layers is "more secure" isn't important if none are "perfectly secure", so having an extra (independent) layer such as a VPN is a very good idea.
You have to decide when to stop stacking, otherwise you'd end up gating access behind multiple VPNs (and actually increasing your susceptibility to hypothetical supply-chain attacks that directly include a RAT).
I'd stop at SSH, since I don't see a conceptual difference to how a VPN handles security (unless you also need to internally expose other ports).
