Constant lag + disconnecting

• Essentially my game will run fine for a bit, then freeze(still keeping me in the realm but entities don't move, tiles don't trop and I don't pick up items), run fine etc, creating a loop of an unplayable annoyance.
• The realm will occasionally close giving me the Internal Exception: java.io.ioexception: an existing connection was forcibly closed by the remote host, putting me back in the main menu
• My internet speed is easily over 100Mbps
• Servers(I tried hypixel, mineplex and a private server I am in) and other games (I tried destiny 2, rocket league, among us and terraria) all work fine with no connection issues
• no other players in the realm experience this
• I have updated Java, reinstalled Java, restarted my PC, changing firewall settings and many other online fixes
• I currently use forge with a mini-map mod and optifine, I have tried it on a vanilla install and have the same issues