ETH is a fantastic hold right now. For the last 5 years ETH has outperformed BTC in the first quarter of each year. I wouldn’t diversify the 4 you have, but you could diversify as you add your positions.
Your goal should to be to ultimately own as many BTC as possible. You do that by dollar cost averaging and trading the alt coins to catch their big moves to ultimately convert that profit to BTC.
Have you considered putting your ETH in Celsius or Crypto.com. You can earn 6ish percent interest while you hold.