You think very hard about a very small portion of requirements which you can deliver in a small amount of time.
You write a User Story (a written description of the requirements from the perspective of a user) with domain experts and stakeholders, then you show that tiny little piece of functionality to your client. Did they like it? Great, you can mkve on to another small little piece. Did they not like it? Then you discuss what should change, them change it until they like it.
Agile is about doing getting feedback as early as possible so that you can know very fast if you're going the right way.
There is no DRM on GOG. You can just download the offline installer, then install it even without an internet connection. It will never ask you to go online because it doesn't need to check anything.
Steam is a ticking time bomb but mostly for the reason that you don't own the games you purchase there and you can't back them up (mostly) so when Steam decides to ban your account or just closes down, you lose all of your games forever.
More people should push for DRM-free games with offline installers, like GOG and Itch offer.
That's why we need a remodel of the economy to go along with it. The only way to stop the creation of more "rich" is to get rid of capitalism altogether.
A step in the right direction would be no pointless MTX, as plenty of other games are doing right now. There are no microtransactions in my copy of Days Gone, for example. Nor are there any in Horizon: Zero Dawn.
And even if it's the popular thing to do, that is not an excuse to let them get an inch. "Oh, but he only beat you a little!"...