I am shocked by your advice.
The 3090 video card is shit in mining for a beginner. This video card is expensive and it heats up. If you were an experienced miner, then the purchase is possible, but not for a beginner.
If you have free electricity, then you need to find a miner with video cards and divide the profit by 50% each.
You do not have risks and you do not need to spend money, and if you have extra money, then it is better to invest in cryptocurrency.
Finding a miner now will not be a big problem.