Just checked out the Mongoose ILI9341 library, using it with an ESP32 and a 2.2" 320x240 ILI9341 with SPI. Working well.
I need to get some higher level functionality (menuing). I'm looking at https://github.com/neu-rah/ArduinoMenu. Learning curve and interfacing to existing ILI9341 library looks a little daunting, but doable.
Before I start hurting myself with this, has anyone seen any menuing systems appropriate to use with MongooseOS?