we often diy walking tours and use gpsmycity.com to plan our walks. On the upper right find "all cities" and then click on the appropriate continent.
You will be rewarded by an alphabetical list of countries with the cities offered. When you click on the city you want you will often see more than one walking tour. One might be an Introductory tour, another may be architectural gems, etc. Also read the articles since the author sometimes writes about bars, cafes, restaurants, and cool little shops.
You will find with each tour an accompanying map that you can download but since I worry that the phone will not function, we also print out the map! Each map location then has further info. I print it all!
Here is an example using Gothenburg.....
https://www.gpsmycity.com/tours/gothenburg-introduction-walking-tour-3991.html
Good luck! (there are many others I use as well, but this is a good start) Have fun!