Generally speaking, a setting with a 10,000 year history could probably compress that down to 1,000 years and not lose a single thing, and getting rid of medieval stasis is by far the easiest way to explain medieval stasis. Few of the explanations typically posited to explain 10,000 years of medieval tech and society actually hold up to scrutiny (and by “few” I mean “not a single one I have encountered, but I’m leaving wiggle room in case there’s a better one I haven’t heard of”).
Periodic cataclysmic events? Unless the world is a constantly churning chaos of multiple cataclysms per lifetime, this will only slow down technological progress. Cataclysms destroy infrastructure which makes it hard for technology to propagate, but they don’t destroy technology that already exists. The technology of the Dark Ages was more advanced than that of the late Roman Empire, just not as much more advanced as it would’ve been if the empire held together. The main casualties in cataclysms are history and philosophy.
Disrupting electronics has a much smaller impact on technology than people seem to think. The only electronic technology that’s at all important to WW2-era tech is electric lights and radio. If your goal is medieval or even industrial stasis, you’re going to need to do something about tanks and airplanes.
A lack of iron won’t just prevent industrialization, it will prevent the iron age. Iron was a big deal because it was really common which meant the iron age was an era when everyone could have metal tools and it wasn’t even a big deal. Bronze, on the other hand, is an alloy of copper and tin, and you don’t generally find both of those things in the same place, which means in the bronze age metal is significantly more scarce. Bronze isn’t actually an inferior material to iron, so if iron is as hard to get as bronze is your main result is that spears and pottery never go out of style. If you want bronze age stasis for a Greek myths game, that works fine, but you can’t simultaneously have enough iron for people to make full plate suits of the stuff and yet say it’s too scarce to make muskets.
Avoiding industrialization due to environmental concerns will only keep you locked into the 18th and early 19th centuries. You don’t need industrialization to have gunpowder armies, so Napoleonic warfare is still on the table.
Outlawing technologies is generally speaking really hard. People have totally tried, the Catholic Church tried to ban crossbows, but it doesn’t really work. Religious sects and political factions also have difficulty surviving more than a few centuries. Most of the religions we’re familiar with today aren’t singular entities but rather a vague coalition of different sects each of which is significantly younger than the coalition itself. Christianity might date back two thousand years, but the vast majority of actual Christian churches are only a few centuries old at most, and Christianity is unusual in having a pair of organized churches that have persisted a long time. Most religions have exactly zero organizations that date back more than two or three hundred years. Political factions and especially secret societies are even less stable. Explaining how these organizations survived for 5,000+ years of medieval stasis is already harder than explaining medieval stasis in the first place, explaining how they retained enough power to enforce a universal ban on technology doesn’t make it easier. You could write a story where the entire premise is that there’s a global hegemon repressing technology, but you can’t just append that to an existing setting to explain away medieval stasis. It’s too drastic a change.
Treaty-enforced de-escalation has a similar longevity issue, it’s not anymore plausible for the treaty to last more than a few centuries than for medieval stasis to be a thing in the first place, and the additional problem that it’s extremely unlikely that the entire world is affected by this treaty. Pacts with gods or spirits, on the other hand, share the issue of being too drastic to be dropped in as an explanation for medieval stasis and then ignored. In reality, having pacts with gods or spirits so important and so far-reaching as to be a total ban on tech past a certain level indicates that relations with gods or spirits are a big enough deal to be setting-defining features.
If iron and magic mess with each other, that probably just encourages wizards and blacksmiths to live in different towns, not for one or the other to cease existing altogether. Most medieval stasis settings don’t actually depend that much on magic at all, because if they did they would not be medieval stasis, they would be magepunk. Having a magepunk society where magic is the norm because it is more effective than and mutually exclusive with the advanced metallurgy that tech more advanced than early iron age has can work as a major setting conceit, but you can’t drop it onto a setting just to explain a lack of tech advancement.
Seriously, just don’t use medieval stasis. I’ve never found a setting that actually needed more than one or two thousand years of history. Usually there’s just four hundred year gaps in the timeline to make things seem more vast, but the actual effect is that there are huge gaps in the chain of historical cause and effect so that the history seems more like a series of unrelated vignettes than the backstory for anything.