Start a dummy account on an emulator and carry your main account on Co-op. Reaching rank 30 to carry in Epic Raids is also not difficult. Do not host public players, be self-contained.
If you wish to mod on your main, at least you have a dummy account to test the waters first.
For GQ modding, see above reply. For senkaimon, just mod a reasonable timing (1min for Normal tower, 1m30s for Extreme tower is fair).
Again, do whatever you want on the dummy account first before switching to the main account. GQ remains the most dangerous mode (mod detection is very strong there), the rest are fine.