I have another paypal account which I am unable to access, Whenever I try to login it shows "we couldn't confirm it's you" I tried calling support but due to covid all lines are unavailable. Now how do I regain access to my account? I made a transaction just yesterday, now I can't access.
Try downloading the app and change it via settings, if not then...
You would need to contact customer services so that they can i.d. you another way and then add your new phone number to your account.
Paypal phones are mostly non operational since covid but sometimes you get lucky. (use the guest option if you can't log in). If there is one available it will show when you click help / contact bottom left of Paypal pages for options available in your country. Live chat is randomly available. You can send them a message. Or have you considered contacting Customer Service via Facebook or Twitter? You can send them a personal message from their facebook or twitter pages. It's: https://www.facebook.com/PayPal and @AskPayPal for Twitter.
Advice is voluntary. Kudos / Solution appreciated.