Do not connect your D cell primary lithium battery to the MKRWAN battery connection. Doing so could cause a fire and/or the battery may explode.
I do not understand what you mean by "resistor divider"? That doesn't sound like it will work properly. You need a low dropout voltage regulator or a buck converter to the regulate the 3.6V Primary cell voltage to 3.3V. You can then connect the output of the regulator to the 3.3V of the MKRWAN.