Malaysia divisions' II is not competitive enough to bring 5 good new managers every season.
With the anti-tanking measures in place right now, I'm pretty sure no league in the world has a Div II team that can be competitive enough to balance both sides, if one side is already too strong to begin with.
We have the same problem in the SBBL. Last season we had 3 crazily expensive teams in big 8, and only 1 in great 8, which actually turned bot. My team was probably the closest to the big 4 (before I decided to sell off my key players and focus on training), and my weekly salary was just slightly above the salary floor. But this season, with my absence (and the best Great 8 team going bot), a newly promoted team ended up leading the conference, but he's not tipping the balance over anytime soon - his roster is still pretty far away from touching the rosters of those top teams, and that's also partly because of him only being able to buy players below 200k salary. It's impossible to buy a championship roster right after promoting. So I guess most of the time such things are out of the question.
However, what you can do is weed out new players and guide them how to run the team well, and hope that they all go into the weaker conference and blossom from there. The newly promoted team I mentioned above was mentored by me for around 1 season, so while he hasn't touched the level of the top SBBL teams, leading the conference in their second full season is quite an achievement, so I'm pretty confident that they'll keep growing. If there are a few more such users, then it shouldn't be hard to balance out the conferences.