Is there any way to add app storage say from 32 to 1TB or must I buy a new iPad

It is impossible to increase the amount internal storage in your iPad - as this is fixed during manufacture; what you have is fixed for the life of your device. 

You can, however, subscribe to a higher tier of iCloud storage - but this is not a substitute for internal storage.

About storage on your device and in iCloud – Apple Support

Manage your iCloud storage – Apple Support

If you have insufficient internal storage for your needs, you have two options:

• Manage the storage that you already have:

How to check the storage on your iPhone, iPad and iPod touch – Apple Support

• Replace your iPad with a model with adequate storage for your needs.

No.

You need more internal data storage? Then, you need a larger internal data storage iPad model.

I always tend to use up close to the usable, internal data storage of any device or computer I purchase.

My next iPad Pro purchase will either be a 512 GBs or 1 TB storage model.

My current older 2015/2016, 12.9 inch screen, 256 GBs iPad Pro is over 50% filled in about 18 months.

Get the highest amount of internal data storage space, in an iPad, you can afford as NO Apple iOS/iPadO devices have expandable storage.

Best of Luck to You!