The pagers exploded with lethal effect because they had commercial grade high explosives planted inside them at the factory, which israel controlled. Lithium batteries can over heat, burst, and and produce significant flames, but it's nothing compared to real explosives. There is security footage of some of the pagers detonating and you can compare them to lithium battery explosions that occur in vapes and cell phones on occasion.

If you had the power to hack EVs, the most dangerous thing you could do would probably be to disable them all during rushour. Every single road in the country would be blocked simultaneously with many secondary effects and likely mass panic.

However, it is unlikely that israel would do this. While they do have a penchant for false flag attacks, the enemies they wish to blame are not technologically sophisticated so a mass cyber attack would not be believable. Further, the response to a mass cyber attack would probably be more isolationism, rooting out saboteurs, security audits of everything - not something israel wants their hosts to do.