I am an American who has owned a home in Guanajuato for 16 years. It has been a thoroughly enjoyable experience. A few unmentioned benefits for the "pro" category are: Property taxes are generally very low in Mexico (I pay less than $100/yr.); service calls and repairs are generally very cheap compared to US; I recently did a renovation and it exceeded my expectations in terms of cost, considerable skill of the crew, and creative flexibility - e.g, my GC had no issues changing up the project scope as better ideas emerged - they are accustomed to this. So, you can potentially improve your place, to the extent required, and hopefully leverage a very skilled construction and materials market.
For Mex. City, an architect friend of mine from Guanajuato moved permanently to Mex. City and he made sure to check the architectural integrity of the apartment buildings he was interested in (to the extent possible). Even with that, his building suffered damage in the most recent earthquake. Mexico City certainly has unique challenges in terms of topography (
https://www.sciencealert.com/mexico-city-is-sinking-at-an-alarming-and-largely-unstoppable-rate-according-to-data). Some other things to consider if you decide to buy in DF (or Mexico, generally): find a reputable Notario Publico for the transaction (one who speaks English if you require translation) since they will handle most all of the paperwork/filings/cursory title check; inquire about title insurance - this is an increasingly available option in Mexico - Stewart Title has an office in Mex.; check if your building has any major assessments forthcoming (I recently heard from a realtor in Spain that on occasion apt. sellers will fail to disclose a pending assessment to prospective buyers - e.g, improvement of common spaces or a buildings facade) which is a liability the unsuspecting buyer inherits. Not sure if this is an issue in Mexico, but just something to consider. Since you have residency if you decide to sell you should theoretically qualify for the capital gains exemption (if you meet the requirements of this - primary residence, etc.) - but something to look into if you think you aren't going to move there permanently and will eventually sell. I would also check short term rental requirements. Guanajuato, for example, has gotten very strict about STR properties and in enforcing tax/reporting compliance. Also, does your particular building even allow it?
I personally love Mexico City. And I wouldn't avoid buying in Mexico just because of general (albeit, well meaning) concerns from people who haven't spent much time on the ground. But owning property in Mexico brings forth challenges (e.g., at some point you will spend a few hours waiting in a line of an agency whether it be for electricity, water, property tax, etc.). But it sounds like you are adventurous and having a great experience there. Best of luck!