What exactly is "everything"?
Logging in with the same Apple Account on the Mac for iCloud that the iPad and iPhone have, should let you access everything that is synced to iCloud such as email, notes, contacts, calendar and any files in iCloud Drive, and photos in iCloud Photos in the relevant apps.
click here ➜ Set up iCloud on your Mac - Apple Support
You can add other email accounts to get access to their email, notes, contacts, calendar and reminders.
click here ➜ Add email accounts in Mail on Mac - Apple Support
You can of course Airdrop any files not in iCloud and if you don't use iCloud Photos, you can transfer photos from the iPad and the iPhone by connecting them to the Mac and using the Photos app or the Image Capture app to download the photos.
click here ➜ Use AirDrop to send items to nearby Apple devices - Apple Support
click here ➜ Use iCloud Photos on Mac - Apple Support
If you aren't using iCloud Photos, click here ➜ Transfer photos and videos from your iPhone or iPad to your Mac or PC - Apple Support
click here ➜ Image Capture User Guide for Mac - Apple Support
Any supported apps from the iPhone or iPad can be redownloaded from the Mac App Store if required.
click here ➜ Use iPhone and iPad apps on Mac with Apple silicon - Apple Support
Beyond that, what issues are you having exactly with the steps you have seen suggested?
What exactly are you trying to transfer?
There is no single packaged transfer or data from iOS devices to Mac which is why you need to transfer different things in different ways.