To be fair, isn't that what happens all the time?
Players on outgoing contracts can sign for new clubs 6 months before the end their current contract.
Spurs announced four days ago that they agreed a transfer with Bayern for Tel. That he'll join the club permanently July 1st at the end of the loan agreement.
Same with Alcaraz:
Everton have triggered the option to make Charly Alcaraz a permanent signing for an undisclosed fee when his loan from Brazilian side Flamengo concludes next month.
...
The permanent deal will see the 22-year-old sign for the Blues until the end of June 2027.
Not sure what the correct terminology is. Pre-contracts perhaps?
Point is, there is nothing that stops Everton from agreeing transfers that will be effective from July 1st.