First-person wording paid off much more when the speaker looked experienced

On-site experience

Reader Note:: Study 4B was an online experiment with 456 Prolific participants in a restaurant scenario. The server was described either as experienced or as new, then said either "I feel like this is an excellent choice" or "It feels like this is an excellent choice," and persuasion was rated on the same seven-point scale as in the earlier studies. With the experienced server the first-person wording won by a wide margin, 5.37 against 4.53 (p < .001); with the new server the gap shrank to 4.30 against 3.97 (p = .030). Participants did read the experienced server as more experienced, 6.01 against 2.07, so the manipulation landed. The paper does not say when the experiment ran.
Evidence:: Experimental
Vendor interest:: None
Sample:: Six online experiments, mostly with Prolific participants; disclosed samples include N=15, 21, 111, 111, 400, 527, and 456, plus 3 independent coders in Study 1.

Good for

Backing budget and pricing decisions in similar situations.

Situations far from the one tested, without checking again.
This was measured in one market. It may not hold where you are.
The source never says when this data was collected. It could be considerably older than the publication date suggests.