MacBook Air slow and won’t start up properly

Hi!

I’m having some issues with my MacBook Air (2020). The battery needs to be replaced but until I can afford it I’m making sure it’s plugged in to the power cable. Last week it died and would not turn on. After a few days connected to the power cable it did and has been working fine.

Last night it worked perfectly but since I hadn’t updated for a while and the automatic updates had failed, I decided that I would try to update it today.

When I logged in I noticed that the fans were freaking out and the computer was running very slow and even froze so I couldn’t use the mouse. I did a force restart, after which it got stuck on the Apple startup logo. Tried a few different solutions for that which made it startup and I could login. However the fans were still freaking out, it was still running EXTREMELY slowly. I left it alone and after 1 hour it still hadn’t started properly. It wouldn’t connect to WiFi at all (could barely search for available networks), would not turn on Bluetooth and would not open settings app. I tried asking it to restart to no avail. I could not open any system settings or information. Force restarted again, got stuck on apple logo once more but managed to get past it. This time it got stuck on password and would not boot up.

I thought maybe the out of date system was part of the issue, so I tried to open safe mode so that I could update it from there. The computer won’t even open safe mode.

Any ideas what might be wrong? Please help.