The current IDE offering of IRremoteESP8266) being v2.8.6 does not support the ESP32 Arduino Core 3.x Timer API.
This patched version of IRrecv.cpp will add ESP32 v3.x support to IRremoteESP8266 (v2.8.6).
Install IRremoteESP8266 (v2.8.6) via the IDE or manually if you prefer then navigate to Documents > Arduino > libraries > IRremoteESP8266 > src and replace IRrecv.h with this patched version
- Here is a pictorial readme if you prefer.