So I want to play on Ps4 but the upload speed is between 500kbps-1mbps (im supposed to have 10mbps upload) and its very laggy, the download speed is good i have 100mbps, im using ethernet, i already changed the router and its the same. What can I do?
I would talk with your service provider about the upload speed. Some things you could do would be changing the DNS on the router itself and checking that the IP address is set to auto or Dynamic in the network settings. I would also try to see what your other devices get for upload speed.
What country are you based in? I'm Australian so I'll try my best..
Ring up your ISP (Internet Service Provider) and tell them your issue, see if there is something on their side that is affecting it.
Maybe also try checking for hardware issues. I see you've already swapped routers which is great, but have you checked connections? For example, in Australia, majority connect our routers to the Internet with phone line cables (DSL). I don't know what types of cables are used in fibre based connections. Maybe see if the cable could be an issue?
Then again, as you said, your download speed is fine but your upload is not. Best guess is there is a "bottleneck" the ISP can try remedy if you call them up and tell them your issue.