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.
Most of the users here are regretting not buying at the lowest price of a coin but do you really know at that time that it really is the lowest price of that coin? And Vice-versa.
In your case its Ethereum. Do you really know that it already was the highest price of Ethereum at time? Of course no one knows that is why you need to trust the project if you really want to gain high profits. Many here are investing into Bitcoin because they trust it and they can hold it for many years.
As for me, I don't have any regrets when it comes to crypto. I used Bitcoin to buy my first computer set in 2019. How much is Bitcoin at that time? Did I regret doing it? Not at all because I don't know that Bitcoin will shoot up in the succeeding years.