Connection issues to specific games / websites

Hi just joining this thread as this is the only place I’ve seen people mention similar issues to me - does anyone know what exactly it is that’s making Virgin Media wifi not connect to certain games?

I’ve had this issue on Pokémon on Nintendo Switch - and it’s also happened at my parents’ place and they also have Virgin Media wifi. I regret ever having this wifi in my own house. I can connect to Pokémon and go online, but it cuts out literally within like two seconds, meaning I don’t have consistent online play and it’s really upsetting. I get the error code 2_ALZYA_0008 when it cuts out on my Switch, saying connection has been lost. I’m sitting literally next to my router and it does this. Are the mods able to offer a solution?