I am looking for a simple CSV with the list of country names, country ISO codes, city, time zone UTC and DST... It seems simple, but I am struggling to find it. Any advice/help would be very much appreciated.
There is IANA tzdb with a list of all timezones. It's quite complex and changing since timezones change too, for example in Russia timezones changed several times during the last 20 years.
geonames offers this both through their API and bulk dumps.