The guys at the hot corner both in 2013 and 2023 are very decisive players. In 2013, that player was Pedro Alvarez. Alvarez hit .233/.296/.473 with a .330 wOBA, and 112 wRC+. Alvarez struck out just over 30% of the time (30.3%) with a solid 7.8% walk rate. But he led the National League in home runs, crushing 36 round trippers in 614 plate appearances. He also had an impressive .240 ISO.
Although Alvarez had some terrible defensive seasons in his career, 2013 was his best with the leather. He had +2 DRS and a -2.8 UZR/150. It wasn't anything great, and if you sat on the first base line of PNC Park, you had to be extra attentive to the game when there was a ground ball hit to Alvarez, but he held his own and did what was needed. Although you couldn't say that about his future seasons or his past seasons.
Ke'Bryan Hayes on the other hand batted just .244/.314/.345 with a .294 wOBA, and 88 wRC+. Although Hayes was about average in the batting average and OBP departments, while coming in above average in walk rate (8.6%) and strikeout rate (21.6%), Hayes's ISO was just .101. He was one of the worst hitting 3Bs in the game last year unfortunately. He had an issue with lifting the ball, which means he wasn't taking advantage of his outstanding raw power.
But in terms of defense, he wasn't just the best fielder at his position., but he was arguably the best defender in all of baseball. Hayes had +24 DRS, a +7.2 UZR/150, and +18 outs above average. Hayes led all fielders in DRS by a margin of two runs. He was fourth to just Swanson, Jonathan Schoop, and Tommy Edman in outs above average. Despite his poor offense, Hayes had +3 fWAR on the season.
Hayes is the best defensive third baseman the Pirates have ever had. Sure, Alvarez's 2013 wasn't the worst year of his career with the glove, but it pales in comparison. Alvarez had a large advantage in offense, but even if Hayes clears a 110 wRC+ next season, he'll be leagues above Alvarez.