10 year verteran and still trash. Send help.

So, I've been playing this game off and on since end of s2. I've accepted that it's just going to be something that I do probably forever and actually want to start seriously improving. My biggest problem I think is that I intellectually know what is supposed to happen in a League of Legends game, but while playing it's like my brain doesn't work anymore. I get tunneled really hard on whatever I'm doing, whether that's farming, going for a kill, chasing, literally any action. I can't see what else is happening so I end up comitting to poor decisions and inting my brains out. How do I stop tunnelling?

Edit 1: I guess I should also mention that I'm playing on NA but I live in Japan at the moment so I have no lower than 160 ping.

Edit 2: https://na.op.gg/summoners/na/bumbismcgee