Because BB is so new, a lot of teams become bots during season. In a country with about the same number of teams as Greece, new teams are only placed in D.III and D.IV. So at the end of last season, there were lots of bots in D.II and perhaps even in the EBBL.
The past two seasons, BB has done a bot cleanup. After the regular relegation of 4 teams (who might have been bots), BB checks if there are other teams that are bots, and if so promotes additional teams from the series below to replace them.
These extra promotions were based on (1) conference finish; (2) regular season games won. It didn't matter how the team did in the playoffs.
In your II.2, Only 3 teams are holdovers from last season. 4 teams were promoted from III to II due to winning their playoffs. And 9 teams were promoted during the bot club based on their regular season record (all were 1st place teams in their conference).
Between IV and III there were likely even more extra promotions, so that teams that finished 3rd in D.IV may have promoted.
At the end of this season, there may be some extra promotions from D.III to D.II, but probably not as much as last season. Your league has 13 teams that either won their conference in the regular season or won their playoffs. Since they've had some success they'll likely keep playing.
And this will be even more true for the EBBL. There is currently one bot in the EBBL, but they probably will have a poor record and relegate normally.
So I would predict that you will not promote unless you win the playoffs. If you were in D.III, you would probably promote based on your 1st place finish and your 21-1 record, but I suspect that not all 1st place conference teams in D.III will get extra promotions. From D.IV to D.III a fairly good finish may be enough.