How do I manage my money in such a way that I have piece of mind? I won't ask for investment advice directly since people are (understandably) reluctant to give it and taking investment advice from strangers on the internet is (understandably) considered a poor idea, but some leads to get started doing my own research would be very helpful, as this is kind of stressing me out.
2. Your money should not be sitting around, that you have correct. However, you should take a holistic view of "investment". You need to find what will deliver the highest ROI for you in the near future. I am not convinced that stocks/financial assets are that for a mid 20s person in Europe. Maybe you seriously need to buy a new computer? Maybe you have some sort of surgery you were putting off and can now do? These things take priority over buying some stocks.
3. Building from point 2, if you can earn 50k in a short stint, you have some serious skill/knowledge about some industry(unless you got very lucky). The best thing for you to do is figure out how to make those 50k work for you in your area of expertise, where you have an actual edge. Maybe you know what is the next great shitcoin? Who knows, point is that the last thing you should do is lazily chug those 50k in an etf and let the market do the work.
If you don’t have a home, might be handy to use that as a downpayment. You’ll get some returns from property appreciation over time (though there’s always a chance property prices will go down).
If you don’t have emergency savings that give you enough runway in case you lose your main source of income, consider a low-interest savings account and put enough in there to make you comfortable you can survive (enough to cover 3/6/12 months of living expenses- up to you to figure that out). you’ll have to accept inflation will eat it away, but such is the life in europe. There’s no real financial instrument with good yield and low risk around here.
If you got all that covered, no debts, no short term plans to buy property, I would dollar cost average into some form of investment (e.g. etfs).
IMO DCA is a good strategy right now because the markets are fluctuating a lot and it looks very likely there will be a global recession. You get to take advantage of falling prices to push your avg price down.
Something like buying 1-2k per week should work well, but mind broker fees
Investing is based on risk and reward.
Risk is the opposite of protection.
Reward is the result of opportunity.
Opportunities are the result of patience.
If you don't know how to invest, don't invest.
Wait for an opportunity you understand.
Good luck.
Addendum: $50k is a lot of money when it is yours. It is not enough to seriously invest using strategies that work for $50million. A person can live comfortably on very safe 1% returns from a $50million vineyard.
If not, that money would be perfect to start a new life elsewhere.