wifi cutting in and out

You can try a Safeboot to clear system caches—easy enough to try.

SafeBoot https://support.apple.com/en-us/HT201262

Takes noticeable longer to get to the login screen, does a 5-15 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc. once you get to the login screen you can reboot as normal.

You may be picking up interference from somewhere. and for me, wifi doesn't always get through the walls of my house. So, I bought and connected a 2nd airport to extend the wifi range. It's an older model (not the Airport time capsule-I already have one of those-it's the flatter one. Easy as pie to setup and use. I have an airport app on my iPhone, plus the 2nd base station shows up under the wifi network, and you can configure it from there. I have also found that the 2.4 ghz band is a little spotty, so I have set up a 5ghz band, and picked a channel which I hope is not being used as often. So far it has worked OK. Other than that, all I can suggest you do is to reset the smc/pmu and zap pram on your MacBook Pro 2015, maybe make an appointment at your local Genius Bar for the one that's giving you trouble. not much of a suggestion, I know......

john b