I wonder if there are comparative tables (fees, devices support, algos support etc) or articles that cover various mining OS (like HiveOS etc). What OS you know about besides HiveOS?
Any input and help is appreciated for research. 

guys, is there a way to mine monero (randomx algo) on GPUs (using xmrig / xmrstak)?

never invest in one currency! diversify your holdings - it is a golden rule.
I would pick top3-5 coins (ETH would be one of them) and add to my portfolio couple small caps (that you can afford in big quantities at low prices). For example privacy ones: Ryo (really promising devs and tech with good aproach), conceal (interesting pos, but a bit risky idea), bittube

You can check Cyptonight coins to mine with ETH.

GTX 1060 is pretty good in performance and price. But the problem with 3GB cards is they don't work on many algorithms. I want to which coins are you mining with 1060?

When lots of buyer buys the bottom nothing happens, the quantity of buy matter if some buy a coin with Half of its original volume then price of that coin will skyrocket.

Not all the new projects are good, but some of them are absolute good. I perfer looking into new coins that have use-case and future growth potential. Some of the low-caps are only on exchanges they don't have any use-case and i consider these types of coins as scam projects.

For everone highs and lows are different, there only two things that we can do in the markets to make money is, buy low and sell high. What else you can do? I think no one would be interested in buying something high or selling at lower prices. Don't get frustrated just trade without any emotional attachment with your trades then highs and lows will make sense.

I also think new coins with smaller market cap are best to invest, especially privacy coins. I don't recommend investing all your portfolio into 1 single coin because it is too risky when it comes to investing in a new project. I've checked out the project you mentioned in your post and they seems good and legit to me and investing 10% of your portfolio into these coins could pay off in the long-term.

My suggestion will be don't invest all in just 1 altcoin it is not a really good idea. Do your own research and try to find out the project which has use-case and actively developing. Coin with a low-market cap is the best to get huge returns in a short period of time, not all the low-caps are good but you can find out some of the best by looking into their roadmap and dev team.
                                                                                                             

If you think halving will affect bitcoin price in the bullish direction then I think the increase in BTC price will also affect altcoin prices then there is no point to sell altcoins right now.

Taking profits at the right time is good,  but I think for some quality altcoins with use-case are good to hold in the long-term.

Before buying any GPU first you need to about the algorithm which you are going to mine, then you can check profitability on what to mine.

80% small crypto projects are repeating this 20X is possible but they don't understand the concept of blockchain, it's not about high prices it's about the use case and useable features. If a coin is only used for trading and doesn't have any use-case then there is no point to buy those type of coins.

I might reach there in the future, but no one really knows when it will hit that price.

I don't think mining a coin on mobile is worth or not, what is the cost of a mobile phone as compared to mid-range GPU? Everyone has his own choices but I'm not really convinced about the mobile mining concept.                                                                                                                       

If you are new you can start with GTX 1060 because they are reasonable in cost and can perform better on GPU minable coins, you can also check all the information about how much you will make with these on what to mine.

Why so lazy my man, check on google. You will find the best answers there

Check out privacy coins they could be a good investment in the long-term.

Does it support RX5700?