The taxes are already high, the population is decreasing, and that's not counting enormous pension underfunding at the city and state level. There has been lots written about this for decades, during which the problems got worse. See e.g. https://www.chicagofed.org/publications/chicago-fed-letter/2...
None of those prove “effectively insolvent” and most are false, anyways.
Chicago population grew according to 2020 census. Then the Census Bureau acknowledged that was undercounted. Any "news" on this is likely using the admittedly bad calculations to push a narrative. [1]
Taxes aren’t particularly high for a city. There is no city income tax and property taxes aren’t in the top 10. [2]
The pensions are absolutely an issue, but huge progress has been made in the past 5 years and they are making actuarial payments as of now. They got a bond rating upgrade recently and are solidly investment grade.
"On October 21, 2022, Fitch Ratings upgraded the City of Chicago's general obligation bonds from BBB- to BBB. This was Fitch's first upgrade of Chicago general obligation bonds in 25 years due to the City's improved financial condition, rather than a change in the rating agency's methodology." [3]