Did you check into proving your net worth? I believe property (houses) also count toward that.
When we did our permanent residency, the man we worked with was extremely flexible in what we used. We were able to show how much money was passing through our PayPal account during the 6 months a year we did eBay, and he was happy to accept that as proof of income.
Here's more, and it gives the number for net worth. Maybe you have that in your retirement account or a house!
Residente Permanente visa applicants must show a monthly income of 500 times the minimum wage => $3,243 US dollars ($61,610 MXN pesos) using an exchange rate of $19:1 ... That income must be documented by 6 months bank statements. ... People who have liquid assets can also qualify by proving an annual average balance of 20,000 times the minimum wage => $130,000 US dollars ($2,464,400 MXN pesos) using an exchange rate of $19:1 for 2020 applicants ... documented by 12 months of bank statements.
Residente Temporal visa applicants must now prove a monthly income of 300 times the minimum wage => $1,946 US dollars ($36,966 MXN pesos) per month (using an exchange rate of $19:1. Consulates want 6 months of bank statements. ... People who have liquid assets can also qualify by proving an average annual balance of 5,000 times the minimum wage => $32,426 US dollars ($61,6100 MXN pesos) account balance for 2020.
