Agree, the only reason you run down a contract is to maximise your wages/signing on fee when you do sign for another club.
I'm not knocking MG, it's a short career etc but after Olise re-signed 2 years ago on £100k p.w MG could have signed a similar deal (as Eze did).
He and his agent clearly thought waiting another 3 years (so losing £50k a week extra) would be worthwhile in the long term.
I strongly suspect MG's agent is asking a minimum of £200k a week for his services and possibly more.
If he joins someone in January his wage demands will be similar so the transfer fee will be quite low as the overall 5 year package (wages, signing on fee/agents fee, and transfer fee) could be c £80m to £100m (minimum £11m wages per year for 5 years, £5m agent fee and £20m transfer fee).
Liverpool's £35m bid was on a low side and they waited until the last minute despite clearly needing a CB all summer. I strongly suspect his wage demands were the issue.