Sry that came out kinda long.
Honestly that's a good point, mind can be trained. I should try it again now that I've had some more practice with it.
It's one of the most recommended and accessible methods to deal with it. Mindfulness meditation or just taking time, sitting down and focusing on the bodily sensations is one one of the most recommended method to deal with alexithymia as over time it teaches the person to become more aware of their body and teaches to associate different bodily sensations with corresponding emotions. Other is some form of journaling as writing down different sensations and what was going on at that time can indicate what emotions i might have been experiencing at that time.
Of course it would be slightly more effective with a therapist, but as it is a years or more long process. The price of that can stack up rather high.
Personally I've been trying to use "Animi" app, which is specifically created for people with alexithymia. It combines both approachs with regular logging of different body signals and sitting down, focusing and taking time to reflect back. It does use a different approach than other emotional tracking apps as it already takes inro account that the user doesn't know what emotion they might be experiencing by starting to guess based on whatever sensations i might be having.