Hi,  i have two of the tapo c510w cams. they were working really great. i was getting 250kb/s with being in the home and on the same connection / network. i was also geting about 150kb/s while i was away from home using the app via cell phone ( apple iphone 15 ) now we are getting 0-40kbs when we are out and 50-150kbs while we are at home on the same network. nothing changed with my provider and we have unlimited bandwidth our plan is 1000mbs uploads and downloads. no other device in the house using the same network is having issues. just these cams. 

what we have tried.

ensured 2.4ghz connection. with dedicated channel 11 and 20mhz. 

reset the devices numerous times

reconnected devices numerous times

updated the app. the cam and firmware

reset the router

factory restored the router 

contacted our ISP to ensure we are getting the bandwith and MBS

connected the cams to a hotspot ( on one of our phones ) then accessed remotley ( still very slow and poor connection ) 

our cameras are also not out of range. they are within 5ft of the router

we also just bought another cam to test this out ( c210 ) and its having all these issues right out of the box

from what i can gather is that there was a firmware update at some point and this is having a conflict with our internet and remote access.