Hello,
In case your simcom module is a Cellular module I suggest you to have a look to X-CUBE-CELLULAR.
It is a Cellular middleware for STM32 that runs on different Cellular LTE CatM / NBIoT modems (BG96, GM01Q, T1SC).
It runs on AzureRTOS and FreeRTOS.
It supports modemIP and stm32IP.
modemIP is cellular IP stack runs in the modem
stm32IP is cellular IP stack runs in the stm32.
stm32IP with FreeRTOS is LwIP.
PPPosif is the layer between lwIP & IPC that can interest you.
It is in middleware : STM32_Cellular/Core directory.
