Same problem here with same vintage MacBook Air. My keyboard and trackpad started freezing up in summer of 2023 (originally, keyboard would stop while I was typing something -- not just on wake-up). It has been back to Apple twice with no resolution (Apple updated firmware one time but that didn't help; other time they said they couldn't replicate the problem – the non-working keyboard problem was intermittent at that point, but now it happens every time I close the computer or send it to sleep). External mouse and keyboard work fine but what a nuisance! I hate to send computer back to Apple because I haven't heard of anyone who has had success going that route. Grrr. Let me know if you find a solution. Here, I'm trying to train myself not to put computer to sleep or to even close the lid – doesn't work for traveling, of course.