If this were only about him doing his job, then I might not take as much issue with the "what" and "how" of what he is doing. However, I believe he- and the Executive Branch as an institution- has gone far beyond Constitutional limits.
As for the concept of favorability mandate, it's my contention that the Democratic opposition lost because they are out of touch, and had no cohesive, clear plan. Republicans won because while they are equally out of touch, they adopted a plan which capitalized on people's anger over policies that are needlessly intrusive, and a government that appears increasingly sclerotic and ineffectual.
I do not believe most critically-thinking folks would vote for unelected oligarchs to be brought into government, drug dealers and violent criminals to go free, and "wasteful" government agencies to be "rapidly disassembled" before a suitable alternative framework was in place. None of that seems to be helping the average American family, but it's not hard to see how it helps Mr. Musk and his cronies. I think a lot of Trump voters simply felt that the alternative was worse, and wanted the newspeak and constant barrage of identity politics out of their faces. Although I didn't vote for Trump, I felt that way myself. Democrats have long since lost the thread there.
On point of wasteful and outdated methods: Perhaps the reason there are still people in a limestone cave doing paperwork by hand in 2025 is that the mechanics of a workable alternative are difficult and no funding line has existed to modernize. Perhaps the reason there are 20M deceased Americans on SS is due to the fact that the SSA needs to track deceased individuals, and may even help them prevent SS fraud. I highly doubt they have been receiving benefits beyond the grave, except possibly in isolated cases of administrative mistakes. Perhaps actual solutions take time.
I do NOT believe Elon Musk is so much smarter than everyone else that he came in and "discovered" all these flaws in two weeks. Were someone external and hostile to Twitter (okay, "X"... lame...) to go in and data-mine their system, I am 100% certain they could "discover" all kinds of waste and organizational issues. Big human organizations tend to be that way.
Apologies if I'm re-hashing arguments already made.