your second question. "what is easiest" is difficult to answer. For a beginner most of them entail a very large learning curve. and it is something you just have to face up to.
I have both Photoshop + lightroom and the full Affinity suite.
Both are now massively complex and cover just about every thing you can think of. in the way of post processing.
I bough the Affinity to check it out, when it was on offer, and in the few years that I have had it, it has advanced by leaps and bounds. However it does not do the two things I need it for most. It has no Library like light room. Nor can it apply the inbuilt camera firmware adjustments for cameras and lenses when processing raw files... In fact its raw file functionality is still extremely basic and not at all adequate. (it applies none of the inbuilt adjustments for Fuji, or any other camera come to that)
Personally I would go for Photoshop + lightroom.
All the various other offerings like On1 RAW or DXO photolab and C1 have their strong points and sometime each take their turn to lead in some way or another. But the Market leader "Photoshop" always catches up in a few months, and offers the strongest offering of all, over time.
I would not be surprised if Affinity catches up in a few years. as they are the only one to scrap every thing, and start again with completely new code. designed to cope with the newest hardware and technology. unlike any of the others This has allowed them to have a fully integrated framework to incorporate everything into a single core code, covering all of their programs. so that you can switch anything between any of them absolutely seamlessly. Even the "photoshop" tribe of programs is clunky in this regard..
However the Total lack of a DAM ( library module) and the somewhat farcical, even risible. Raw processor massively limits the usefulness of Affinity for now. Nor is there any indication that they are working on either. ( but they might be, and certainly should be) were they to do so I would most certainly use it. and pension off Photoshop.
Though I would fully expect Affinity to Jump in price were they to complete their flush of programs. I suspect its present extremely low price, is an acknowledgement that it is , as of now, very incomplete.
Their raw processor can be considerd no more than a placeholder in their system code, till a real deal comes along. In the mean time we must use something else.