Diversifying your portfolio is not a must, it is adviced but not a must for you to diversify especially when you are not in a position to manage or handle the financial and emotional risk involved. If you must diversify as well, do your research and make some few solid choices with projects that are promising, don't invest in too many alt coins so that you can keep proper track and not make unnecessary losses. If diversify, set durations to monitor your investment, if any seems to be going under the table with no hope, be sure to bail.
For a maximalist, I think it isn't a necessity but with an ever-changing society with the likes of crypto, I think for most people it's a must. Always the best course of advice to DYOR especially if you're new to the game and if you just blindly invest into some shitcoins then expect to wet your pants later on if your portfolio goes down to -80% or more and if you can't handle it then good luck.
People wont learn until they do get the experience which it is a really common scenario on where everybody is heading up specially when you are just new into crypto.
You would really be seeing those kind of volatility that you havent seen before and would realize that making money or profits wont really be simple as it sounds.
Diversify while you can because things arent sure to happen if you dont put up much work and effort.