What coin is closest to perfection?

In 2017, I was intrigued with crypto so I bought 500€ of ETH to learn how crypto transfers work and what the fuss was about. After a few months I sold for about 100% profit. Sure I could have made a lot more money if I held longer but I don't have any big regrets since my priority wasn't to make money in the first place.

That said, after reading what developments have happened in crypto since then I got interested again and I'm willing to spend a small amount on 1-2 currencies. The question is what coin? So many new ones have launched since then. When I bought some ETH it was still a "new" and relatively unheard coin for those not familiar with it. Everyone was talking about Bitcoin. These days, I hear more about ETH than BTC and it almost feels kind of outdated when I read about its high gas fees, still proof-of-work, etc....

So my question is: with all the new developments what coin(s) are closest to perfection?

My criteria would be:

• must be secure
• must be reasonably decentralized
• highly liquid aka reasonable adoption rate. Even the best coin is useless if no one uses it
• must be available on all the major exchanges
• small/zero carbon footprint

What coin fits these criteria the best? Pls don't shill your own coins...