I lost my main internet for a week due to a power cut that left my main router in a funny state. It had to be factory reset then WiFi SSDs and passwords were reset. My office internet comes down a very long ethernet cable via two switches and a router. I had problems with my router and it got factory reset. Unfortunately I didn’t set this network up and didn’t realise that the network had two routers each doing DHCP and consequently it took a week to get things right. At one point I;d do a ping from my desktop PC and the answer would come back as IPV6, It was totally ignoring IPV4 requests, pings to domains with the -4 parameter were unreachable. Not a fun week.
My Pi which plugs into one of the switches and my desktop PC which also plugs onto the same switch would not talk. Both could see the internet but my Pi could not see Microsoft servers. I’d tried everything, even giving it a permanent IP rather than a DHCP but that can cause issues if the DHCP issues an IP address the same.
I do rather a lot with my PC and the Pi and having them networked is much more convenient than not. I use WinSCP for copying files and Putty if I need to connect in.
In the end, I bottled out and burnt the Raspberry Pi OS on a SD Card and booted from that. One hour later I’d installed all 295 updates and then installed VS Code.