>It must be frustrating for UNHCR employees too, because I’m sure they’re doing everything they can to make the system work… it just isn’t.

Depending on the country, the backlog may not actually be UNHCR's fault. In most countries, it has an advisory/supportive role (or no role at all) when it comes to processing asylum claims. In countries with no or limited capacity, it may be responsible for the process with some support from the government.