Have you tried booting into Safe Mode which loads only the minimal drivers and disables Startup & Login items?
Have you tried creating another user account in case a preference is causing the problem?
Have you tried rebooting both your router/access point as well as the computer?
What is the exact model of your laptop which can be found by clicking the Apple menu and selecting "About this Mac". What version of macOS? Are you using the original Apple SSD or a third party SSD?
Is the WiFi signal strength between around -40db to -60db? Is the WiFi noise level somewhere around -90db? Option click the WiFi icon to get this information.
When the system wakes up, maybe some background tasks are interfering and taking up too many resources for the WiFi to reconnect properly. If you wait five minutes will it reconnect on its own?