I would say speak to the student privately - hallway or something like that. Ask what you can do to help that student. Collaborate with your colleagues too there might be a strategy that works well in another class that you can try.

They can be doing a warm up activity, drawing a mindmap, reflecting on last class, journaling, reading, meditating getting a ready mindset.

I love using nearpod, chat feature in Teams, or jamboard to document learning.