The most immediate threat to your finances from playing online video games among the options provided is 3. losing track of microtransactions while playing online.
Microtransactions can quickly add up and lead to significant expenses without the player even realizing it. Unlike the other options, which may have indirect financial implications (like potentially affecting academic performance or causing fatigue that impacts productivity), losing track of microtransactions can directly and immediately impact your financial situation. If you're not keeping an eye on your purchases within games, you may end up overspending on virtual items, subscription services, or in-game advantages.