I need help with how to trade at all time highs.... I feel like I have good ideas on when to sell, but then I miss tons of gains.

Ok so I have a good amount of NVDA and AMD and I'm making a shitload on money recently. Like more than I know what to do with. I dont know when to sell and take profits. I took a little profit on my AMD a little bit ago, then it rocketed, same with NVDA in the past I take profit then it rockets. I just dont know when to find the ceiling of a stock. I use RSI to try to gauge it, when its over 70 I usually start getting pretty nervous of a collapse, but sometimes it pumps constantly over 70 RSI. AMD right now is above 70 RSI for a while on the daily chart. There are no resistance levels after all time high which I use a lot in my trading, and its just difficult for me to find the ceiling and I seem to pull out too early then miss tons of gains. I want to lock in good profit near the top. What do you guys use to find the top? I also try to stick by the famous quote be greedy when others are fearful and fearful when others are greedy... Well right now market is extremely greedy and I'm getting a little fearful, but I dont know when I should sell and get out of this! I was going to wait until NVDA earnings and probably sell a bunch then. AMD I'm not too sure of. Its kinda looking a bit weaker now, I kinda want to sell soon.