To Daycare or NOT to Daycare a 4 month old GSD puppy, that is the question.

I'm raising Copper, a working-line medium-drive GSD, solo, and I'm weighing putting him in daycare 1 day/week once he's fully vaccinated (around 4 months).

The appeal: I work from home (but have to go into the office 1 day/week), so it'd give me one full day to tire him out, and give him socialization and play with other dogs. Some structured energy-burning sounds great, especially for a high-drive shepherd.

But I have reservations and want honest input:

• Is 4 months too young? Fear periods, still-developing temperament, etc.
• Do dogs pick up bad habits at daycare (over-arousal, rude play, barrier frustration, learning that other dogs = playtime)? I'm working hard on engagement with ME and calm settling, and I don't want daycare to undo that.
• Working-line GSD specifically, are they well-suited to daycare, or does the environment overstimulate/overwhelm them or bring out reactivity later?
• How do you vet a good daycare (group sizes, temperament matching, staff-to-dog ratio, rest periods, red flags)?
• Alternatives that give me a break + tire him out without the downsides? (Half-days? A dog walker instead? Structured playdates with known dogs?)

For context: he's my first GSD (grew up with dogs, horses, and even trained big cat cubs at a rescue, so I know drive, but shepherds are new to me). He's smart, intense, bonded, and a typical land-shark at this age.

Working-line GSD owners especially, I'd love to hear your daycare experiences, good and bad. Did it help, hurt, or was it neutral? What would you do?