I read through this thread and will add my thoughts based on my city. These will probably be unpopular because they don't fit with people's preconceived notions of how the game works.
First, if you have high unemployment, you have zoned too much residential. Dezone them until your unemployment drops to a manageable amount (you determine this but I keep mine between 4% and 8%). This will also keep your homeless at a low rate. Keep an eye on it as you go back to expanding your city and only zone enough residential to fill the demand for jobs being created.
Second, the "office bug". I've been confused by this because I haven't seen it at all. It makes me think this is due to having too many offices zoned, and/or a mod is causing the issue. I have no offices with only 5 employees. The smallest is a low density office with 45 employees. The high density offices have well over a hundred to hundreds of employees.
Something that I was doing wrong at the beginning was zoning based on the Demand Bars which is the worst thing we can do. Ignore those bars and zone what your city needs when it needs it. The demand bars will cause you to over zone and causes all kinds of problems with cities. Hopefully that gets fixed at some point.
Keep an eye on the profitability of businesses (commercial/industrial/office). If you have a lot of unprofitable businesses, look into why that is. Have you zoned too many or is there an issue with exporting? Specialized industry seems to be an issue at this point but it's still being investigated (see this thread for more information:
https://forum.paradoxplaza.com/forum/threads/my-industrial-profitability-keeps-being-low.1732606/).
CS2 doesn't work at all like CS1. It's much more complex and takes a more nuanced approach to city development and growth. You can't sledgehammer your way into a successful city by zoning what you want. You have to manage the growth.