Then why did it happen 3 elections in a row?!

We had front-page news about how the election was "hacked by Russia" and trump cheated for over a year after his first win in 2016 (let's not pretend that keyword was chosen accidentally); They tried to put him in jail for it. In 2020, trump did the exact same thing and went even farther with it. And in 2024, the DNC tried again to claim cheating happened.

How many cycle of this BS do we need to go through before we accept that elections need to be done properly and safely?

The entire point of a democracy is that elected leaders get their legitimacy and their acting power from the certainty that it was voted by the population. Not everyone will agree with their ideas, but the majority do and we all agree to follow their lead because that's what the population want. If the vote is compromised, everything falls apart.

If the "will of the people" turn into the "will of an intern at Dominion who fucked with the code and rigged the election" or "the will of Pakistani hacker", it breaks the entire system.

I have to seriously disagree on the particulars, here.

The Russia allegations ranged from "Russia hacked DNC servers/accounts to interfer in favor of Donald Trump" (demonstrably true in several instances) to "Russia hacked voting machines" (very probably false). And then in 2024 the DNC quickly accepted election results.

By comparison, Donald Trump still claims that he legitimately won the 2020 elections, the majority of his base still believes it, Fox News spent years spreading that message even though their own journalists thought it was bullshit, etc.

I maintain that this is a systemic problem and a better system would not have given Trump the leeway to do this, but let's not pretend it's a bipartisan issue.