I think out of everything here, Avalanche probably has the most potential.

The Terra ecosystem is very interesting but I don't think that it's going to go anywhere in the long term, there are simply way better alternatives out there that are up and coming.

Polygon is a good short term scaling solution for ETH but at the end of the day the Layer 1 ETH network has to be scaled itself for Ethereum to succeed, so as soon as ETH2.0 rolls around I think that MATIC will take a big hit.