The problem with your ingredients is that both (green tea and toasted rice) only have a mild scent to begin with.
The scent mostly comes from essential oils. Things that are rich in essential oils like lavender flowers, eucalyptus leaves or mint have a very strong scent that can be overpowering. But it's easy to extract their scent into a neutral oil and use that to infuse things like candles or soap. In fact, most tutorials for "tea infused candles" use mint or lavender tea instead of green tea!
Both green tea and rice have only a very small amount of oil, so it's harder to extract any scent from them. You should heat 100 ml oil in a pan to medium-low heat and steep tea leaves in it for 15 minutes. If the oil is too hot, it destroys the scent. If the scent is still not enough, add more tea. Don't worry if your tea bags break apart in the hot oil, that's normal.
In theory you could extract more scent by putting the ingredients in alcohol, but mixing alcohol into candle wax makes the candle melt and drip, the alcohol makes the drips themselves flammable and such a candle poses a high risk of burning down your home. The only safe options for adding scents to a candle are essential oils or scented wax melts.
There are many candle scents available by many manufacturers, including green tea. They usually contain instructions like "add X drops of oil to Y weight of wax". If you find a scent too strong or irritating, you should add less to the molten wax.
Paraffin wax can hold the most scent without any additives.