For the difference between mobile and consoles, it depends on if you have publisher or port team backing or not. Many indie developers do not get devkits, do not get proper access to Nintendo Switch Online, PlayStation Network, or Xbox Live networking, do not get performance monitoring tools, and do not get any documentation or support. For them the most that happens is they export the necessary files in a reviewable archive format and send it in for approval, hoping that the game engine they chose to use properly functions on the given console and that there won't be any major problems that will cause them to go through the review process again. This also applies to any major updates or patches later on. The consoles treat these indie developers the same way Steam, Itch.io, and GOG treat their developers -- as vendors in a storefront, not as equal business partners vital to the operations of the platform. For these indie devs if you want the above features you have to hire somebody to do the porting for you or you have to go through a lengthy and expensive process to be approved to use them. Most console releases of well known indie games like Celeste, Shovel Knight, and Rimworld are handled by port teams for this very reason. On console, if you're below the AA tier you're paying for the cost of the privileges others get instead of you.
However with mobile storefronts at the start everybody gets treated equally since they all have access to the same limited number of features and get the same level of (some would say neglectful) automated support. For the most part Epic Games goes through the same process of uploading a game or program and waiting for approval that Jimbob does. It's only afterwards that the level of access changes. It's this way by design. Not only because early on there were no big names in the mobile space and so no real tier system was necessary, but also because quantity is valued over quality. There are about a thousand uploads to Google Play a week (I haven't found strict data on how many are only games, but the process is the same for games and apps so it doesn't really matter), versus between twenty to thirty on PlayStation and Xbox. Creating unique avenues and methods would bottleneck things horrifically for mobile. As a developer you get an informal discount for the relative lack of quality control and increased competition you'll be facing.
This cost is very evident in the prices of the games. You won't ever see games that aren't asset flips or shovelware below a non-sale price of $1.99 on Xbox Games Store, but you'll see plenty of $0.79 games on Google Play and Steam.