homebase throttling upload

hello,
wanted to put a feeler out to see if anyone has experienced their camera setup affecting their homes network upload speed.

my place has a total of 5 cameras (e30), a doorbell(e340) chime and a homebase 2.
lots of activity outside gets picked up (so much so that i had to drop sensitivity to 1 and make the motion detection area tiny for each cam). All cameras are set to store to the homebase wirelessly.
my home network ahas 1gig down but only 40gig up (limitation of my isp). when the homebase is plugged in and the cameras are all active, i notice my upload speed drop down to literally 1mbps. it was only after swapping multiple routers and even getting a separate modem that i thought it could be the cameras. unplugged the homebase and sure enough full upload speed is back.

all this to ask a couple questions

1. have you experienced this?
2. is this normal for the amount of cameras i have?
3. how can i change my cameras to save to a local sd card rather than the homebase without completely removing the device and resetting everything.

thank you all in advance!