Most managers I've had appreciate being told individually. If there's any chance at all you'd take a counter offer, you should let management know privately. Theyre less likely to counter if you're news is known publicly.

(Imo never take a counter but always listen to one. That's valuable market information)

6 years later and I definitely regret taking a counter offer.

Once you've announced your intention to leave, even just privately, it changes your relationship. Accepting a counter-offer is just going to leave things awkward.

Very awkward I'd say. A counter offer is just adding insult to injury, e.g. why was is not offered with salary adjustments earlier.

In my experience only two scenarios offer a substantial raise in pay: Switching jobs or Getting a new role/title.

Somehow just doing your job well is not enough.