iPad 3 forgotten passcode can’t restore

Hi all

I’ve found my old iPad 3, and can’t remember the passcode. I’ve tried putting it into iTunes recovery mode and plugging it in to my MacBook, but it isn’t showing in finder. And as I’ve got Catalina, there’s no iTunes.

ive also tried putting a working SIM card into the iPad, and it showed a network service. So then went onto iCloud and find my iphone. The iPad was showing offline, but it was also showing the iPads battery. So I did the erase iPad, and it was showing pending in iCloud. However nothing happened on the iPad.

please can someone help.

many thanks in advance.