English is a fairly simple language that through the years has shaved off a lot of the complexities.
No grammatical genders - In languages like French, German or Spanish, you need to know the gender of the words, and there can be multiple, depending on the language, more than 3 genders.
Fairly simple declension - I refer you to this Wikipedika article to see all the ways you can have articles and pronouns be in German, depending on the grammatical case and gender of the word. And you need to use the correct one.
Fairly simple verb conjugation - Want 3rd person? Just add an "s". Want past tense? Just add "ed". That's it basically for verb forms. Sure, there are irregular forms for past tense, but even those mostly follow a similar pattern, e.g "bought", "fought", "thought", "caught".
Behold this Wikipedia article again explaining all the verb forms you can have in German (look at those tables each containing a verb form lol). Oh btw, it does have irregular forms too.
The spelling is a mess, true, like, we don't even have enough alphabets, and the way words are written are a complete mess compared to how they are spoken.
But comparing it to Kanji where you have learn roughly one symbol for each word? Where you literally can spend years learning it? Not learning the language itself, just learning how to read it. Oh, did I mention there are also 2 other alphabet sets that Japanese does have? Don't worry though, that's only around like a hundred or so additional symbols.
Well, the Iranian government itself claims around 3k, and based on what we know they have kinda every interest to downplay it (they literally shutdown internet during it), so you know if they are claiming thousands, it's gotta be bad.
HRANA published a detailed report containing around 7k deaths, with names and other info such as age, and a lot of times pictures, and at the time of that report, an additional 11k were also to be confirmed. They aren't just pulling it out of air, they list the literal names.
The UN estimates it to be in the tens of thousands.
According to Times, they have info from two senior official of Iran's ministry of health that it's around 30k.
The guardian, again, based on various info from morgues, medics and graveyard staff, estimates around 30k.
Iran International based on similar things claims more than 36k.
Put together all the various footage of dead bodies and stuff (BBC says 300 were in just one mortuary), and you see that the number isn't just pulled out of nowhere, with multiple things backing it up.
It's not that hard to kill that many if you open free fire onto large concentrated gatherings of people. Iran has a population of around 80m, 30k is around 0.03% of the population. A football stadium alone can hold 100k people. Imagine you have gatherings of thousands, and you have armed squads, machine guns or whatever just shooting, and you see how those numbers aren't really that hard to reach.
You are comparing the wrong things. Gaza is more bombing of stuff and some war going on here and there, and less deliberate killing of people who have all gathered in one place. It's not really a "let's go and slaughter masses" thing. Yes, people die in situations where bombs fly around, but it's more of a... side-effect, and people can evacuate places. It's also not an intense all-out war situation either.
You should compare more to stuff like El Fasher massacre, which also has reports of tens of thousands of people being killed in a matter of days.
You could also compare it to more intense stuff like the Rwandan genocide, which had around 500k-1m people killed in around 100 days.