Big rules nerd here, and you may already know this but for anyone seeing this new tech who doesn’t: Tamiyos safekeeping (or other indestructible sources) won’t protect a planeswalker from losing loyalty counters to damage, or for dying to zero loyalty. The reason is although it can’t be destroyed (indestructible), it can still take damage, and taking damage is what removes loyalty counters. It’s why the various Gideons that turn into creatures both make him indestructible and prevent damage, to avoid this situation.

Ofc, Tamiyo’s does protect against “destroy target/all planeswalkers” type effects