Macbook Air 2020 restarts when I close the lid

Thanks for your suggestion to put my Mac to sleep. Unfortunately, that didn't work. When I opened my Mac the next morning, I had to type in my password when I opened the Mac, and then I had to wait while the Chrome windows and other applications started up.

The current situation isn't the end of the world, but things didn't always work this way. I started noticing this behave a couple years ago, but prior to that time, the Macbook Air would just remember all of the open apps, open windows, etc., whenever I opened up the lid. Now, it only remembers everything if I reopen the Mac within a relatively short time. I haven't kept track of how long a "relatively short time" is within any precision, but I know it happens if I open the Mac the next day. On the other hand, I just reopened the Mac about two hours after I closed it, and everything was immediately there , just like I left it.

And when it goes through the process of bringing back what I had running the day before, sometimes it loses a things I have written into a web page, so i have to try to reconstruct what I was doing. This aspect is even more annoying than just having to wait for a minute while the Mac brings back what was running previously.

I should also note that my wife's iMac opens up with all of the browser windows, Word files, etc. immediately available in the same state she left them when she left the day before, the week before, or whenever. My Macbook Air used to behave the same way, but not any more, and this is what I would like to correct.