Ok, now
AT+QCFG="nat",0
at+qnetdevctl=1,3,1
at+cfun=1,1
When the modem is back just run your DHCP client and see whether it will work without additional commands.
I just realised that I suggested the wrong sequence of commands in my earlier post.
Reset command should be used before at+qnetdevctl, not after and at+qnetdevctl should be issued after the modem is back after reset.
One more thing to mention: the new drivers produced by the Waveshare script are too big, you can compare the sizes between the old and new files. Their build script probably needs some tweaking but that is outside of my area of expertise.