Mac and iPad Pro are both very capable platforms - with some clear differences.
If you like a fixed keyboard, the Mac may be a better choice. By contrast, for portability and flexibility, the iPad Pro might be a better option if the onscreen keyboard is adequate for your needs. While you can add a keyboard or folio keyboard with trackpad to the iPad Pro for use at a desk or table, this arrangement is less useful if you tend to work on your lap. For graphics, iPad Pro wins hands-down - offering direct interaction with the screen and the opportunity to use an Apple Pencil. Both platforms can be used with an external monitor if required.
If your budget can extend to both Mac and iPad Pro, you will have benefit of both worlds - the two devices having complementary capabilities and can be used together.
Specifically to iPad, whichever iPad model you choose, you would be well advised to purchase as much internal storage as your budget might reasonably allow - as internal storage (and other hardware) cannot be changed, upgraded or extended. The available internal storage is fixed for the entire life of the device. If you run out of internal storage for your documents, photos and other data, you will forever struggle and become a source of frustration. It is far better to have more storage than you need, than to need more storage than you have.
A good rule of thumb is to quantify how much data storage you will need - add a healthy margin - then double it. If you are unable to quantify your data storage needs, it becomes more difficult. Whilst I and others cannot cannot make definitive recommendations for your personal needs, objectively I would council against purchase of any iPad with any less than 256GB storage, 512GB or more offering greater headroom as your needs and storage requirements evolve. 1TB/2TB models of iPad Pro also benefit from 16GB RAM (boosting performance), whereas the other models of iPad Pro M5 have 12GB RAM.
Within the Apple Support Communities we see regular tales of woe and disappointment when storage requirements are exceeded, necessitating replacement of the device; by contrast, we never see complaint of having too much available storage. It is relatively easy to fill limited internal storage space; perhaps consider higher tiers of storage as providing room for growth as your needs develop or mature - potentially extending the useful usable life of the device.
Also consider the functional differences between WiFi Only and WiFi+Cellular models of iPad. Aside from the obvious Cellular functionality, only WiFi+Cellular models include GNSS/GPS location capabilities - which may impact any Apps or features that require accurate and consistent location data, such as Mapping.
Purchase of a WiFi+Cellular model provides access to precise location services, but does not commit you to using Cellular connections. WiFi Only models of iPad have no Cellular or GNSS/GPS functions at all.
