A: Water is wet
B: It is not !
A: What is your argument ?
B: I said so ! So it must be true !
A: "Water is wet"
B: "No it isn't. Here's a bunch of evidence that it isn't"
A: "I'm going to make an unrelated comment trying to show that you didn't say anything"
B: "I'm going to more accurately portray your lack of argument using the same format"
Like bro... You're the one who has 0 argument. I at the very least brought examples of how leveling is not necessary.
Your entire argument hinges on progression through things that are not directly tied to levels themselves. That you're, for some reason, conflating as intrisicly part of a levels as a mechanic.
99.99% of everything provided by "Levels" can be provided by other means without levels. The only thing intrinsically associated with levels is an increasing level number, which is meaningless on its own.
Levels are really only so popular due to the reliance on the outdated and often detrimental experience system. Whereby acruing incremental "Experience Points" from doing a variety of tasks is the main way of providing progression, meaning you do these various tasks enough until you hit a threshold to then gain an increase in power (Ignoring level scaling) which is most easily understood by "Gaining a level".
Such a mechanic is not necessary. As there are plenty of other ways to gate progression. Many games like to outright reward skill points or upgrades from completing activites directly, rather than relying on them giving generic "Experience Points" to build towards a level up. This can be certain side quests, optional activities or even "Challenges"
Collecting items it also a common way to provide progression. As mentioned prior Elden Ring's DLC has the player gather Scadutree Fragments that provide players with damage and defenses. Games like the Zelda series has players gather Pieces of Heart which every 4th one provides an additional heart container for more health. Doom: The Dark Ages has the player collect resources to spend on upgrades for their equipment.
In Table Top games, it's a popular rule to use the "Gain levels at story moments" thing in lieu of experience. Whereby all players gain the benefits of an increased level at certain points during the story (Before you say anything, "Level" here only really matters because the game rules are based around gating features behind a level progression system. It would be trivially easy to simply provide the benefits without it being a "Level". Adjusting the "Feat" system so you simply get a "Feat" each time you "Level up" which provides the features you'd otherwise gain)
There's even non-incremental progression systems. Like is seen in Metroidvania games (As well as things like Zelda and Darksiders) where your progression is based on acquiring new abilities, usually after beating a boss or progressing through a dungeon. Whereby the progression is simply you gaining that new ability which allows you to interact with more of the game.
Other ways of gating progression can also provide better gameplay experiences, by freeing up players to play how they want, rather than trying to chase after the incremental experience gained from doing various tasks (Such as how someone may want to not bother getting a key for a lock because picking it provides experience. Or stealthing past an encounter is undesirable because you gain experience for killing everything).
In addition, alternate means of progression can feel better to a player and make more sense in context. Gaining an increase of power because you did something that rewarded you with a tangible power increase is sensible. While gaining an increase in power because you happened to cross an arbitrary experience threshold by doing something inane like opening a box or walking close to a "Point of interest" is kind of silly.
As well as making things more simple to balance, as you don't have to try and micromanage experience gains to ensure that players (With varying playstyles) encounter a smooth progression without enemies becoming too easy/difficult based on how much potential experience they have accrued at any point in time.
