diversifying investments tips

Hello sub, I'm 25M. I have been following this sub since quite some time and learned good amount of knowledge regarding investing. I need your advice on how I can invest better. I know there is no one who can answer this correctly but I can learn from your opinions and thought process. I have around 100k invested in Robinhood. Mostly in diversified companies. My top companies are MSFT, UNH, NVO, RDDT, PLTR contributing to almost 40% of my portfolio. 15% cash in SGOV. Rest on some data center, chip, health care..etc stocks. Right now I feel like my portfolio kind of have too many stocks (around 50). So I want your advice on how I can bring it down to few stocks. I want to invest for a long term but I feel like selling a stock if it hits my target and I get some profits. I'm up like 10% last year. I lost most of the gains by selling early. And I haven't invested in any ETF yet, How much of a portfolio should be in ETFs for safer side. How much to invest in sold stocks like mag 7 or with good fundamentals, how much to invest in early stage companies to experiment, and how much to keep cash. It would be great if someone can help me by providing their experience on this. I can add like 4k every month to keep investing consistently. If you can add your way of doing due diligence in short it would be even better. Thanks in advance.