I have heard about putting my roku on another submet but i don’t know how to do this. Any thoughts 🤔

I believe that would rely on the modem settings… If you buy a router (eero, Google WiFi, etc.) and connect it to the Ethernet port, you could create a separate network and your modem would see your router as a single device. I have T-Mobile Internet but don’t trust them with my data, so in conjunction with the above, I have all my network traffic pointed towards AdGuard DNS (Personal Plan)(they have a free version that works well, but you can’t customize it).