MacBook Pro 2020 not charging

My macbook pro has not been properly charging for about a month now. This occured randomly (No damage to the laptop), with both ports stopping working at the same time. If shut down and left on the charge the laptop will charge slowly, taking about a week to fully charge.

I have tried:

• Restarting laptop
• Different chargers and adapters
• Cleaning USB C ports
• Manual NVRAM reset
• Disconnecting and reconnecting battery

Earlier today the laptop recognised a flash drive I connected and I could see the data on it, but it still would not charge or recognise a connected charger nor was it able to charge another device. However after runnning diagnostics and taking it to a repair shop where they disconnected and reconnected the battery it no longer recognised the flash drive.

I am just wondering if anyone could identify what the problem could be, and whether it is fixable or not.