There are multiple things that haven't been said in this thread that contribute to this whole Van Dijk situation.
Correct me if I'm wrong, we've had no 100% confirmation that Southampton has even received a bid that's even remotely worth it. I'd be surprised if we have gotten an official offer that was substantial. Don't forget that Van Dijk has been injured for 6 months. His rehab is taking longer than we originally thought and that could be scaring off (at least for now) most interested clubs.
We've heard about the 50, 60, 75 million euro assessments but we haven't heard any word of an actual offer.
But to be fair... for all we know Southampton could sell next week, although I doubt it...
...Because there's rumours we are being bought by a Chinese company today. Why would we sell our biggest asset while we're in the middle of a takeover? The new company would definitely want to take an assessment of the assets before making an groundbreaking club moves. (Selling Van Dijk applies here)
I think that we'd want to get our feet underneath us with this takeover before we make major moves.
And again... Who says that Van Dijk is upset? His Twitter post yesterday? It's a sponsored tweet for Nike, it's likely innocuous. Van Dijk has mentioned before that he and his girlfriend have gotten settled in and are happy in Southampton. He's the team captain, plus the team's best player, and we're consistently getting upgrades to our positions.
Ralph Krueger has said we don't need to sell any players to keep profit, therefore we're in no hurry to sell anyone. If we fire Puel (likely) and hire someone like Tuchel/Schmidt, we make a good case for at least a Europa spot next season.