Adobe has a lot of Photoshop apps.
Search the IOS App Store for just Adobe.
If you want to maintain an all Adobe workflow, for Photoshop, in order to get most of Photoshop's functionality on a computer, you will need to use all of the various Adobe Photoshop apps to work with.
If you use an older version of Photoshop and not the current Adobe creative cloud suite with subscription, most of Adobe's apps, in order to better integrate will need to pay for a CreativeCloud monthly subscription or login to your Creative Cloud account if you already pay for a subscription.
If using an older version of Photoshop, you will need to use a Cloud service like DropBox or Box or some other Cloud Service, like Apple's iCloud Drive, Amazon Cloud Drive or GoogleDrive to be able to bandy your work back and forth between your iPad and computer.
Adobe, I guess, won't or doesn't know how to create one version of Photoshop on iOS that is a close approximation to Photoshop on a full blown computer.
Adobe has broken up full Photoshop into a variety of apps to cover different Photoshop areas.
You'll end up using multiple Photoshop apps to cover everything you do with full Photoshop.
You'll end up using multiple apps for doing a great many things, that maybe easier on a computer, no matter what, anyhow.
This is how iOS works.
There is no one app that will cover everything you may need.
Working in iOS is mostly working with multiple apps.
For image editing work and digital painting and illustration work, you will find you will have to constantly import/export files from one app to another.
If you do not like this multiple iOS Photoshop app approach, then your only alternatives are Pixelmator for iPad and maybe, in addition, Procreate.
I use quite a few image editing apps and painting apps, but both Pixelmator and Procreate are the apps that are at the top apps on my large iPad Pro.
There are other image editors and painting apps that you can use
I have quite a few.
Here's my own incomplete list of creative image and drawing apps that I have installed and use.
In no particular order.
Pixelmator
Procreate
SketchBook/ SketchBook Pro
Sketches Pro
Concepts
Forge
Inspire Pro
ibis paint
Art Studio
Memopad
Graphic
Touch Draw
Over
Transfer
HD Photo Sort (an image/document folder based organisation app)
Photogene
Photo Toaster
TItleFX
Retype
Union
Filterstorm
Photomotion
If you want to add more fonts to your iPad that apps can have access to, search for the app
AnyFont.
Good Luck!