I did a netinstall refomat of my hAP ax2 and was not sure what the default from factory npk were installed?
From factory is the only npk installed ?
routeros-7.8-arm64.npk
wifiwave2-7.8-arm64.npk
Or was there more than that installed by default?
Also, after a netinstall, is it possible to netinstall and also get the default config like when I first turned on the device?
What is the best way to get the device back to factory defaults?
Using netinstall I do not believe wifiwave2 package is applied as well automatically.
(I am not 100% sure it can be done directly from netinstall, never tried that)
It can be added manually afterwards (which you will have to do or wifi will not work).
When you netinstall, there is an option to keep old config. Default this is not selected, so after netinstall without old config, default config will be applied.
When you do Netinstall, you need at least two packages - routeros and wifiwave2. Anything else is optional, as you need.
As @Normis indicated (but did not “shout it out loud”): when doing netinstall, it is possible to upload (and install) multiple npks in single operation.
I already figured that out from his response 
The default configuration is still there after a netinstall. By using netinstall it ensures it’s the “latest” defaults (since the default sometimes change between version, e.g. V7.8 to v7.9). If your configuration was default before netinstall, there is no need to use “save the config” option & in fact be better not to since it will use the newest defaults.
You can always get the default configuration using /system/reset-configuration but that essentially what happen when you use netinstall without saving the config, so should be no need for that.