With land investing/flipping becoming more democratized/accessible  (so many landed courses, tools, resources etc), current prices/RE trends etc, is it still worth getting into land investing/flipping for a brand new RE investor ?

New year, new laws (Senate bills 205, 206 & 207).Effective January 2, 2025, Michigan landlords can no longer consider a tenant's source of income when screening them. 

I just had tenants move out of my investment property (duplex) without paying for the last month's rent, and the damage they inflicted onto the property exceeds their security deposit amount.

In this way, I never need to be concerned about justifying my charge to their deposit because the damage is clear and obvious. 

I'm brand new to Bigger Pockets and just recently moved to Los Angeles County.

Delta has not charged me extra for the new block.

was looking to add brand new SFH to my portfolio.

Being a brand new unit you have rehabbed you might have to get her out rather than potentially ruin the whole unit by an act of her negligence.

Was this a flip or a new primary? 

If it's not a holiday, I would say, "No, the deposit remains in place until your lease ends."