I am bullish on ETH. There are 1.4 million transactions a day on the network and it is increasing. There is also a major upgrade package coming soon that will increase the speed of transactions and lower the cost. There are some players trying to cut into the ETH business, but as of now, they are very small. Cardano/ADA is frequently mentioned as an ETH competitor, but it only has about 25,000 transactions a day.
You timeline should be 4 years, not 3 years. The next Bitcoin halfing will likely happen in early 2024. This will start the next bull market run (after this one wraps up at the end of the year).
Here is a great video. BTC and ETH are great cryptos that will coexist since they serve different purposes: