I have a Roku 2. It is approx 7 metres from my router and works fine across NowTV, Prime Video, Netflix etc.
However it has bad buffering issues on Iplayer and NBA League Pass. The feed is normally fine for approx 10-15 minutes and then constant buffering / freezing. This is the same regardless of whether others are using the network or I am the only one using.
I have restarted roku, refreshed connection, deleted the apps and reinstalled and still facing the same problem.
There are five different Roku players that have the number 2 in the name, so we don't know exactly which player you have. A model number would help.
However, all players with a 2 in the name are old, and unless yours is the model 4210, it likely just doesn't work well with the latest versions of the channels. Those older players have much slower processors, less memory, and in general are not adequate for use with the latest channels. I have a 2 XS in my desk drawer, and it's been there for years because it can't keep up.
Dan Roku Stick (3600), Ultra (4640), Ultra (4670), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.