YAC isn't the only way to be a threat. Thielen's ADOT was 11 yards last year. He's stressing a defense beyond its first level.
Renfrow's 2023 ADOT was 5.6 yards. He's settling into a soft spot under a zone and the defense bets that they can rally and tackle before he gets to the marker. That kind of popgun slot receiver play is fine, but we should hope to be able to find that ability in someone who can also bring another skill, whether that's a vertical threat, or some jet sweep/screen game YAC ability, or even just being very large and blocking well. Every time we trot Renfrow out there, we limit what the defense has to worry about.