Selling Stocks when Markets are Down

First of all I only have some Basic Knowledge about the stock market, so I‘m not sure if the following is a thing or not.

People say that the only way of truly achieving gains long-term with stocks is by Value Investing, which of course also plays a role here. Now I also heard that you shouldn’t trade too often, as the trading fees itself are one of the reasons for lower margins. However, as brokers nowadays only charge you about 1€ per Trade (referring to TradeRepublic in Germany, but I guess it is the same for other neobrokers like Robinhood) you barely pay money for a trade. Therefore, wouldn’t it be possible to sell Stocks in times of recession, in order to buy them back until they start rising again? Did anyone do so and gained more profit this way compared to not selling and rebuying?

I know that time in the market beats timing in the market and that you can‘t actually know if its only a dip or markets are gonna crash, BUT this is about companies you actually believe in and where you have the feeling that because of a specific business-unrelated situation (e.g. Covid 19/ Ukraine crisis) prices are gonna be down for a while and maybe even for years, but then will recover again.

So this is not about stock-gambling, but rather a way, where you use the money of selling (a part of) your stocks at the beginning of a crisis so you can buy them again, when the situation slowly starts to improve and when prices are still down.