Those slide-on tags are good, much less jingly and annoying.
My spaniel recommendation is more for the teenage era… a bear bell
They are like extra large cat bells, on Velcro straps. Spuddog went through a phase of vanishing off into the thickest undergrowth possible on his hunts - he was never far away but I couldn’t see him. Could hear him with his bell though, and as it was on Velcro, no worries about it getting hooked up.
My other strong recommendation is gundog training. You may never want to shoot over your dog, and that’s fine (can’t guarantee you won’t ever want to shoot at it…
). But the working types especially have generations of instinct to get into the undergrowth and find something to hunt, so gundog training helps you to channel that. I used to have an old woolly gloves rolled into a ball so so it smelled like me and throw it into ditches and bushes for Spuddog to hunt out. And I had a small stuffed toy that lives in my boot so again it smelt like me, for the same reason. Find a positive, modern gundog trainer and see what they can do - watching a spaniel work is great fun, whether they’re looking for pheasants or for your old sock 👍