Most likely it was my fault. One of the basic strategy I started to use was selling verticals with 68% chance of success with breakeven price at 1 standard deviation away. If you are right you should win $1 but if you are wrong, you lose $2. In theory, you would break even if you do just that (minus commision). But you can increase your odds of win by closing positions at 50% of max win or loss. You can further read news and reddit and close your positions earlier if something seems off. However, a lot of training videos such as TastyTrade said that news should be already reflected in the prices, so it should not require too much attention.

The mistake I made was probably because I pretty much ignored online forums, news, etc. Maybe I started to read too much about algotrading and wanted to automate my trading.

Last year, all I did was look at upcoming earnings, search each company on reddit, /r/wsb, Twitter, etc. If it seemed people are expecting that company will beat estimates, sell puts spread that is expiring same week. Due high volatility before earnings, you can earn decent premium even with only a few days left before expiration. Also since we have been in bulls market, so I selling puts was kind of safer bet.