Here is how I stated it on another thread talking about Declan Rice:
"I don't think he is worth 100 million, but then again my bias towards attacking minded players means I don't think any defensive minded player, including Rodri or Peak Busquet is worth 100 million.
But my valuation matrix is different. Clearly City Management has a different valuation than I do. Because they clearly thought Rice was worth something around 90 million or more. That's about 50 million over my valuation.
But like they say, a player is worth what someone is willing to pay. Regardless of what my personal dumb opinion is on how valuation should be viewed.
But here is mine:
Established WC attacking player at top club : 100 million or above is okay.
Established WC attacking potential player at Midtable Club: 40 - 75 Mill is max
Established WC defensive players at Top clubs:
50 - 75 mil
Potential WC defensive players at Midtable or foreign club: 25 - 60 Million.
Good Role players: 10 - 40 mill
By my valuation system, you can see we are already overpaying for Gvardiol.
And that's why I don't take my view on valuation seriously. I have to simply accept that Clubs value players differently. And it isn't my place to judge that value. Just to be happy when my club agrees with my valuation and bow out when necessary."
In short, I probably think he is worth about 75 - 80 million Euros tops