How do I transfer Affinity 1 purchase from MacBook Air M1 (2021) to iPad M2 (2024)?

Nobody is forcing you to buy the Affinity Universal License. If all that you want is Affinity Photo V2 for the iPad, they sell that by itself for $18.49.

https://affinity.serif.com/en-us/photo/#buy

Nobody is forcing you to buy it, either.

If you don't care for Affinity Photo's features or pricing ($69.99 for individual desktop platforms, $18.49 for iPad), you are free to consider alternatives. Such as:

• The Adobe Photography (1 TB) subscription plan, to which you subscribe for a year at a time (billed monthly), at a cost of $19.99 per month. (The $9.99 month plan that included access to Photoshop, but less cloud storage, is no longer available to new customers.)
• The GNU Image Manipulation Program (GIMP), which is free, but does not run on iPads.
• Developing your own Photoshop-level iPad photo editing app from scratch, at your own expense … followed by giving it away in the App Store, or selling it in the App Store for much less than $18.49 a copy, if you think that $18.49 is too much to charge for this type of software.

There is no migrating a macOS application to iPadOS as the operating systems and application interactions are entirely different. All Affinity v1 products have been removed from the respective Apple App Stores and only the (upgrade expense) v2 applications are available.

Contact Affinity, or purchase the v2 applications.

You might be interested in some of the items on the FAQ page , e.g.:

"What does the launch of V2 mean for existing users? Do I have to upgrade?

Upgrading is completely optional and, if you wish, you can continue to use the original apps for as long as you like. While V1 will no longer receive any feature updates, we will endeavour to fix any critical issues which may be caused by operating system updates for as long as is reasonable to do so."

…

"Do you offer upgrade pricing for V1 users?

Yes! Anyone who owns V1 can upgrade to a V2 Universal License for 25% off. Plus, you’ll also receive a premium add-on bundle with your purchase, for free! Learn more about these upgrade offers."

If you bought an Affinity V1 Universal license, that would have included versions of all three applications (Photo, Designer, and Publisher) for all three platforms (Mac, Windows, and iPad). However, if you never got around to downloading the V1 iPad apps before V2 came out, I don't know if you could do so now.

If you bought individual Affinity V1 applications for the Mac, and never purchased the iPad versions or a Universal license, the answer might well be "If you want iPad versions, buy them."

You may want to direct your questions to the application vendor:

https://affinity.serif.com/en-us/

From one of the Help pages on the site:

"I have a question related to my account. Who should I contact? 

Please contact affinityorders@serif.com."