iPad Mini 4: backup Mini 4 and transfer data to Mini 6

Situation:

I'm preparing to upgrade to the Mini 6. Today I opened my old desktop to backup my iPad mini, and it crashed. When I opened it again, iTunes was GONE! (The music is still on the computer.)

I have a newer computer, but it's a laptop (LG Gram 2022), and doesn't have enough storage available for the 74 GB of data on my iPad.

Questions:

• can I backup my iPad to an external hard drive (using the newer computer)?
• How do I transfer my data, apps, etc from my Mini 4 to a new Mini 6?

Thanks