The process is a little different for the last year, which I didn't know until today.
From Passan (https://www.espn.co.uk/mlb/story/_/id/47538606/mlb-2026-tarik-skubal-detroit-tigers-record-arbitration-contract)
"On top of that is a rarely used provision that allows players with more than five years of service time to compare themselves not only to past arbitration-eligible players but to everyone in baseball. Meaning that if Skubal were to choose, say, peak Max Scherzer ($43.3 million a year) or Zack Wheeler ($42 million) as his comparables, he could make the case in front of an arbitration panel that because of his special achievements and consistent performance, he is worthy of a salary similar to theirs."