Help with privately transferring WhatsApp data to new phone

I would like to transfer my WhatsApp data (conversations, photos, videos) to my new phone. I also want to transfer other data such as contacts, apps, etc. I know I have to backup the data to google drive. My family has the password to my normal gmail/google account that I usually use so I'm worried they will be able to see data I backup.

My question is, should I make a new Gmail/google account only for the purpose of transferring/backing up this data to my new phone?

If I use this new account as my google account when setting up the new phone, will this become my default account on that new phone or can I use multiple google accounts?

Or maybe I'm wrong about everything and someone can explain how to transfer whatsapp data without worrying about about my private data being exposed to family. I'm not very smart when it comes to these things.

Any help is greatly appreciated