After reading Freek Jansen's VI article today (thanks
@VanDeBank), it seems that both Ajax and Timber's camp have held off all work pertaining to the player's future until recently. Ajax wanted to extend Timber's contract during the season but decided to focus on ending the season successfully rather than holding talks with Timber's camp. Many other clubs were interested in Timber throughout the season, but neither Ajax nor Timber's camp entertained the interest. Recently, however, Ajax have commenced their contract extension talks with Timber's camp, and the player's camp also visited Manchester United's London office. We'll start to see some further developments on this in the next few weeks.
I don't think any of us knows the player's inclinations at this time, but if he decides to renew his contract with Ajax, then we'll have to look at other option this summer.