Help me out here

I am debating someone on youtube about this topic and I need some help, any suggestions?

This comes from the person with which I am trying to argue with.

Well, Nintendo DOES sell their old games, they have for over ten years on their e-shops. However I also think it would be better for Nintendo to sell playable ROMs on something like Steam, or even open their own PC storefront. Throw in those bonuses you mentioned and, in theory, it would cut down on piracy.

You do understand the purpose of advising people to pay for things on the second hand market, right? A lot of people firmly believe, or at least say, they have no options or recourse other than going straight to piracy, which is untrue. They are available, and they may be more difficult and more expensive, but you do have more legal and moral options than piracy.
It depends if any of that actually matters to you, and I don't know why people who don't really care use this as an argument.

And of course the second hand market are "scalpers" when it suits the argument. Back when EA attempted to destroy the used games market, people were adamantly against it. Furious that EA would even attempt to prevent us from buying used games without penalty.
But as soon as it becomes an argument against piracy, all of a sudden resellers are "randos" and "scalpers" and suddenly people only want to "give money to devs directly". The second hand market isn't perfect, just look at PS5's, but let me tell you, I have been able to secure the future of many games I own now because of it without resorting to piracy.
And here I thought people around these parts would jump at the chance to acquire games legally and legitimately while keeping the companies they hate out of the cash loop.

I know I am not going to change any minds, but that doesn't make the discussion meaningless. This conversation isn't about converting others, it's about affirming ideas and being able to rationalize your beliefs effectively. It has become apparent that there NEEDS to be some discourse on this topic because this air-tight echo chamber has given way to absurd and ridiculous ideas like "It isn't stealing if you never intended to buy it".

"Oh so you're a dumpbro, right? Then prove your legally owned copy of Mother 3."