Unless you are looking for secondary effects (e.g., heat your home in winter), the aim of bitcoin mining is to return more in bitcoin than you would invest.

2020 to early 2022 was one of those very rare periods where mining was incredibly profitable.

But if you look at how much in hashrate some big miners claim they are plainning (i.e., orders to come from the ASIC manufacturers yet), and the halving in less than two years, ... it's getting to be really unlikely that a rig bought today (e.g., for 0.3 BTC) will return that same amount (0.3 BTC) above what is spent for electricity.

There is no way today to know the future hashrate, the future exchange rate (as you would be paying for the electric bill from the BTC proceeds), and the future secondhand market value of the rig at disposal, so mining is a gamble. The downside risk can be less than investing in bitcoin, but the upside can be greater (i.e., 0.3 BTC investment returns more than 0.3 BTC) so that's the reason many chance it. But the odds are not that great.

If you are just looking to fiat gain from mining, just buy bitcoin and hodl.