This didnt start with Trump. This has been decades in the making.
Reagan and his team pushed for the unitary executive theory of government, but the Dems back then pushed back when they sought to put it into practice. Any time a SCOTUS decision didnt go their way, the screaming about activist judges rose to the heavens.
Reagan killed the air traffic controllers union, PATCO, and tried to marginalize other unions of government workers.
Reagan tried to ignore black letter law to fund the Contras in Nicaragua with money earned by selling arms to Iran, and his aides lied to Congress to try to cover it up.
When it all came out during the end of the Reagan administration and beginning of the GHW Bush administration, Bill Barr was the AG that recommended that George HW Bush pardon the Iran-Contra criminals, so that Bushs involvement in the scheme would not come out during trials.
Mitch McConnell, more than any GOP member of either house of Congress, alternately threw sand in the gears of any Democratic administration and gave away the powers of Congress to GOP presidents.
Generations of GOP firebreathers spent years undermining confidence in the US court system.
Generations of anti-science grifters spent years undermining confidence in the medical researchers, climate researchers, and agricultural researchers
Generations of religious wingnuts spent years convincing their followers that government is a tool of Satan, except when the GOP is in charge. At that point, government is the absolute tool of God.
Generations of Real He-Man idiots spent years telling us that guns are the answer to everything. Amp up the TSA at airports, security at sporting events, cops in schools, wanting to arm teachers, and put more guns in everyones homes. Got a problem? Violence is the answer namely, beat the hell out of THEM before they beat the hell out of you.
Generations of folks afraid of sex have fought against equal rights for all people, regardless of sexuality. Be afraid of the gays, because they might want a wedding cake. Be afraid of the lesbians, because soon men will become unnecessary. Be afraid of the bi folks, because they are shiftless and untrustworthy and promiscuous. Be afraid of the trans folks, because they are coming for your kids.
Reagan put Rehnquist and Scalia on SCOTUS, followed by GHW Bush adding Thomas, and his son putting Alito and Roberts on the big bench. These folks laid the judicial groundwork for the judicial malpractice that SCOTUS has become known for in recent years. (Presidential immunity is not exactly what the founders fought for.)
Trump didnt invent any of this, but he sure managed to harness it all and pour gasoline on the dumpster fire to aid his own mega grifting, and he is now dragging the country down as he does his thing. But it didnt start with him, and blaming solely him lets a whole lot of other folks off the hook.