Sims 4 Launch and Playtime causes Internet Connection on PC to die completely.

Hi there! 

I hadn't played in a little while and so bought some packs today to get back into it. Noticed that upon launch my internet connection went down. So restarted the router, unplug - wait 10 minutes - plug back in, as well as my computer. Internet seemed fixed until I opened up The Sims 4 again, when it immediately died for things like Youtube and Discord. So the entire rest of the computer. 

It's worth noting that no other device in the house had any issues at all whilst The Sims is running, our wifi connection is 250MBPs and wired is around 800MBPs. So a good connection other wise.

I scrolled other forums and found similar issues. Here is the testing I have completed and fixes I've attempted so far. 

- Restarting computer and modem: listed above
- Reinstalling EA app and subsequently the game and all DLC: No change
- Allowing The Sims 4 through Public and Private firewall in Windows Defender: No change
- Running both EA app and The Sims 4 executable as administrator: No change
- Setting The Sims 4 executable to run as administrator in the compatibility properties: The Sims 4 would not launch
- As the PC is on WiFi, I tried an ethernet cable: No change
- Mobile Data from my Mobile Hotspot: No change
- Launched The Sims with no other unnecessary executables running: No change
- A very old forum suggested removing legacy content but I did not have a legacy content folder so was unable to reproduce.

Further information, I run no Mods or CC, have no anti-virus installed. (Windows defender is advanced enough) and have no VPN installed. 

I've never had this issue before, and though possible to play without any internet connection, it would be very nice to be able to utilise the internet whilst playing. If anybody is able to help that would be much appreciated :)