[Swordmaker]

However, at the end of the night, the laptop doesn't detect my wifi signal. It shows it's running in System Prefs-Internet. So I restart it and it works. I'm wondering if I changed a setting without realizing it? Rather an odd bug. Any clue?

Resetting the System Management Unit on a MacBook:

1. Shut down your Mac.
2. Using the built-in keyboard, press Shift-Control-Option on the left side of the keyboard, then press the power button at the same time. Hold these keys and the power button for 10 seconds.
   If you have a MacBook Pro with Touch ID, the Touch ID button is also the power button.
3. Release all keys.
4. Press the power button again to turn on your Mac.

Instructions for desktop Macs.

1. Make sure everything you’re working on is saved, then Quit all apps. If something refuses to quit, use force quit under the Black Apple Menu.
2. Force a shutdown on the Mac by holding the power button in for ten-fifteen second until the screen goes dead,
3. Wait about thirty seconds
4. Pull the computer’s power plug from the wall or from out of the computer, or switch off the power strip the computer is plugged into.
5. Leave it unplugged or the power switched off, for fifteen seconds, then plug it back in
6. Wait five seconds then restart the computer. You should hear the startup chime.

This procedure resets the System Management Controller, clears out any bad RAM and forces everything to reread defaults.

If this doesn’t solve your WIFI disconnect problem, the problem is likely in your WIFI router’s lease settings. Some older ones have short lease terms and disconnect the clients after a short time, a day, several hours, etc. this is configurable in your router.

[The Westerner]

Sword,
This Macbook 2017 doesn't seem to have an on/off button. Hmm. Nor does it have a USB port, only one port to put the (new shaped) plug. I will need to purchase a converter plug with USB ports. I think they were going for “almost an ipad” with this one.
My router continues to connect to other devices so it's functioning. Perhaps it has a limit of # devices in use? Tonight I'll try turning wifi on/off from the onboard icon.
Thanks again for all the help.
T.W.