Staking is low risk though. Having just enough to stake will be an investment for a long term as long as its earning. The risk will eventually turn higher when the bear market starts and just like the POS coins last 2017, they were profitable but today some of them just shutdown like that Minex.
It is hard to make a passive income if we don't have the right coin because I see that many coins offer people to try to use Masternode. The new coin will hard to compete with the existing coins which already give a good return from the staking. There are so many coins which offer to the stake, and most of the coins are not yet listed on the exchanges, so we don't know how good the coin will work in the future. If you really want to stake, I suggest you to try to stake Dash coin, but the price will not be cheap
I think the MN hype is already gone, it already reaches its peaked in 2018, but as usual it didn't give the investors the supposedly profit. So I don't think this is just possible in 2020. Although the formula still work but I the numbers of crypto enthusiast thinking that MN is going to give them that huge profit is no longer there. Of course anyone can claim 300-400% returns, but the risk involved is very high. You might as well try and trade and do day trading than pushing yourself to a MN, just saying.
Masternodes however needs more investment not just for the collateral but for the VPS that you need to pay monthly.