Deepin & Windows dual boot - still booting only Windows

I've recently installed Deepin by creating a partition on my SSD (50% each). I already had Windows 10 installed, then I installed Deepin 20.3 from a bootable USB and it went without a problem. When the installation finished I had to restart it (as requested by Deepin). The problem is that now I don't get any boot menu or anything like that - Windows automatically boots up without any way to change it. I'm using an old Optiplex 3