Did Jimmy have some established bond with the phone?
Yes and no, its a reoccurring thing in the show that the various contestants get attached to an item and it becomes part of their identity. In S1 Betty adopted the riot helmet for some reason:
and if I recall, Vance had some sort of bat he always would drape his arm over while standing around. Josie had her plushies and I can't really remember how Letty or Sylvia coped. The nonstop barrage of hateful TTS and sound effects, lack of sleep and the stress of getting fucked with by other contestants and production seem to make the contestants latch onto some sort of security blanket item just to cope and when its screwed with they seriously do not like it. Not even prison is as chaotic and damaging to the psyche as being on this show and the one constant Tai(Simon in S1) stated that he dropped out because he was stressed to the point of wanting to physically attack others, and Tai is an extremely ponderous and slow talking individual. If you pulled half the shit that goes on during a fish tank season in prison you would get shanked to death by multiple parties, add in a host of mental issues and you can see why some spaz the fuck out.
The phone wasn't really the issue here, the production crew know that Jimmy was unstable and prone to attacking people when stressed, Sam and particularly Tay had him in a stable pattern for the better part of a week where Jimmy would acknowledge he was deteriorating mentally and would just go decompress in his room or away from people. Production started fucking with him from 11pm until something like 4am with near nonstop barrages of TTS calling him a dog fucker, after being placed at the bar by Tay specifically to be alone and decompress while she tidied up the furniture for the challenge. Then they forced a beef session with Danye (who instantly surrendered just so he could sleep,) Jimmy and Tay get literally every item of theirs stolen by Shinji over the course of the night and he blamed Brittney for this because he felt like she was laughing at their misfortune when they woke up and noticed the theft. In reality it was Tai that woke up in the middle of the night, greeted Shinji and then just rolled over and went back to sleep because he didn't give a fuck. Over the course of the next day a combination of Trish, Britney, production(or fans buying fishtoys) kept putting Jimmy into stressful situations and any time he would try to retreat to decompress they'd instantly pounce him with a new stressful situation. Jimmy would go to the room only to have "a fan" buy the vacate a room for an hour fish toy just to flush Jimmy back into the general population again. Ultimately I think this spergout was entirely engineered by Jet because he was laughing his ass off during the second beef (the one Brittney started) where Jimmy was incel ranting at Trish. Sam, Ben and Vance seemed very tense and uneasy about the whole thing.
He obviously didn't learn his lesson because he later came up smirking and tried selling access to the video to the various contestants fully oblivious the the extreme liability issues he is exposed to. Creating the conditions leading to a crime (assault and battery) could expose Ben and Jet to low level charges for endangerment as there is weeks of video footage showing Jimmy to be unstable with a predilection to attacking women, and literally that day half the staff was following Jimmy around to ensure nothing happened only, for them continuously put more fuel onto the fire. Obviously Jimmy is an adult and responsible for his actions but the staff are fully aware of his conditions and purposefully aggrivated them. Even if Ben and Jet manage to avoid criminal charges (highly unlikely any charges will be filed) they still run a severe risk in civil court if Brittney decided to make a stink about it and played hapless victim instead of triumphant conquerer.
tldr; contestants get stressed and get a security blanket item to cope, Jet kept fucking with every method Jimmy used to cope with stress and it ended up with a 90lbs girl getting thrown. I'm sad Jimmy went out this way but it really was getting tiresome treading around this particular landmine.