I'm new player of this game .. on PS4 with tactician mode

This mode is challenge but hard , very hard .. ohhh
Enemies are same or higher 1-2 level can destroy my party TT

Please tell me that
- Final Bass or final battle ,what level of enemies are same
or higher than my party ?

- Important trick for tactician mode
.. maybe talents / wpns style or skills

I hope that .. I can play this mode until finish game
.. the great game for me ^__^

Thank