If the phone stays stuck on the boot animation for more than 20 minutes, boot back into TWRP, perform another data wipe, and re-flash the ROM file.
By following this guide and choosing the right ROM for your Oppo A37F, you can experience the best of Android 6.0 Marshmallow and beyond. rom oppo a37f android 60 top
I can then provide the direct technical links and exact software package variations needed for your specific device state. Share public link If the phone stays stuck on the boot
Select > Advanced Wipe and select Dalvik Cache, System, Data, and Cache. boot back into TWRP
Boot back into TWRP Recovery, perform another factory reset/wipe, and re-flash the ROM and GApps files.