I can share, just had that happen today.
Friend has a 2020 MBAir (the last intel model) complaining that the battery won't charge, and now has to use plugged in to power all the time.
When I tried it, would not boot, extremely slow, even to load the boot picker screen. I could not get it to boot, until I did several resets. It was so slow, I thought it was continually freezing up. But, I waited, and eventually booted to the normal system (which is Big Sur 11.4 - so needs updating) Could not connect to Wifi, and the extreme slow speed led me to open it up to check for liquid damage (too common, in my experience)
Found a dried liquid residue inside, but directly under the left wrist rest, and found a tiny hole in the -- battery!
Looks like it had been swelling, and somehow developed a tiny hole, which relieved the pressure (almost no swelling, but the battery in that area feels "odd/spongy" The battery health reading (Full Charge Capacity) shows 950, compared to a factory-fresh amount that should be around 4400. So, the battery is way beyond needing replacement (especially with the old leak)
I have not ever had a completely dead battery in a MacBookAir, and have never seen how slow that gets, until now.
Battery won't charge at all, and certainly won't run the MBAir on its own. Some tasks that fill a window with information, such as showing apps in System Information, finally shows a message that the Mac was too slow to load the information. I think I waited about 10 minutes before that little message appeared. So, if it won't run on the battery, a MacBook will be unusably slow. Lots of activities just time out. It's terrible. I am looking forward to using this laptop again, after replacing the battery.
