I wouldn't buy a lot of coins because you will have a hard time monitoring the progress of your investment. In my opinion, you can focus on at least 5 coins including Bitcoin. Imagine of you are monitoring 10 coins and only 3 are giving your profits and the rest are giving you nothing but losses. You need t monitor the projects of those coins, developments and progress. That is on top of the daily updates in cryptocurrencies where one fake news can cause a wide spread drop of price of all coins.
better simplified in 3/4 main coins, especially for coins that focus on pair trading. btc is the main point in this case and then bnb can be the second alternative. the rest can focus on coins with a lower marketcap with a short trading ratio.
The technical aspects, as well as the fundamental news as you say are very important.