My Apple Watch SE second generation won’t charge at all and it won’t turn on.

You may have come here from the related article at the top of this page. Did you try every suggestion in that link? If you did and nothing worked, the next step is to schedule an appointment at your Apple Store Genius Bar for evaluation and option.

The link does tell you how to force restart. You need to hold both the digital and crown and power buttons at the SAME time for several seconds until the Apple Logo appears. If you held them a long time and the Apple logo didn't appear, you need Apple service.