The problem is specifically related to the latest Avastar Marvell driver released by Microsoft, version 15.68.17022.122 - As this is the driver in the driver pack, listed, it will not solve the problem.
You need a previous driver that works. The driver from 2015, however, has issues with 5g signals.
The driver 15.68.17021.121 is from a few months before 122, and that does seem to work, but I don't know what other issues 121 may cause.
You can download a .cab of the previous drivers from the following Microsoft website.
https://www.catalog.update.microsoft.com/Search.aspx?q=marvell%20semiconductors%20
Choose the 121 driver, or other previous driver. Download the cab. Double click on the cab to open it, and move the files out of the cab into a folder on your computer.
Open Device manager and choose to update the driver, with files on your disk. Then choose the folder where you placed these extracted files.
NOTE: the driver IS signed by Microsoft, so you won't get any errors. This is an official previous release, from a Microsoft website.
In addition to complaining to Microsoft, please go to the Marvell website and click, "Talk to us" and fill out the form to submit a complaint about driver 122 for the Marvell Avastar wifi card.
https://www.marvell.com/support.html
Perhaps someone will pay attention to this problem.