There are several solutions listed on this link, but see my suggestions before proceeding - https://windowsreport.com/default-gateway-not-available-windows-10/
Start with solution 7.
(N.B - while solution 7 might work for a while, the problem might return, and one of the other solutions could be required.)
Given that you're on a laptop, I would then try the power-saving suggestions in solutions 3 & 4.
(And then try 7 again)
Failing those, try solution 1.
(And then try 7 again)
Failing that, now try 2, 5 or 6.
Unless you have reason to believe anti-virus has done something, such as you've been tinkering with it before this problem happened, ignore solution 8.