it seems difficult to descend rapidly enough to achieve the next restrictions as shown on the chart,even with speedbrakes.
You have another trick. As long as you are not ATCspeed restricted, youu can get an even better descent by bumping up speed towards Mach/IAS limits. You really drop out of the sky with incredible descent rates, but there is a limit of 3000fpm within 3000' of your sector safety altitude. If even that won't work, you just have to tell ATC.