If I am given a chance to go back to 2020 I would hold my ETH very tight and never let go, when covid was hitting the world at its best I thought it over and I sold 24 ETH which I bought at 120$ each, I never knew I was so damn lucky to buy at that price, learn to hold tight if you believe in a project, there are countless of projects in past years that are way bigger in value right now.
Your regret is almost the same as mine. At the start of the pandemic I had 10ETH in my personal wallet. I held it very firmly, but at that time my finances were very bad. I was fired from work, the pandemic worsened the situation, and my savings were slowly running low. without thinking further I sold all the eth I had, because by then the price had gone up. but when my finances improved I didn't think about buying eth again even though at that time the price wasn't too different from when I sold it. a year later in 2021 to be exact, I realized that the decision at that time was the wrong choice and I regret it now.
I'm currently trying to buy back little by little and will hold onto it for years to come. no matter if many people say ethereum is too high or too expensive, i stick to my current decision, buy it for a long term investment.