He is, not really disputing that.
But a ton of his value is tied to defense, not the bat, where he's right around league average. This is like trading Kirk for the 2021 version of Espinal if you saw Espinal as a starting SS and needed one - elite D and was on pace for 4+ WAR with even above average bat. Now the value from the bat between Espinal and Varsho is very different, Varsho has power, swings and misses a lot and chases alot. Espinal doesnt hit for power, but sprays it around, contact guy. If you had the belief that Varsho was going to take leaps forward with the bat and step more into a 120 wRC+ range ... different story, though I'm not seeing much in his profile from this season that makes me think that kind of improvement is imminent.
Would people really be lining up to trade Kirk for 2021 Espinal if the area of need was SS rather and the OF ?? I doubt that. As much as it makes sense in a WAR for WAR situation, it's not really necessary to give up well above average bats to get well above average defense in return. Rightly or wrongly, defense is and always has been cheaper to get via trade and free agency.