For the subject of which coin to buy for investment purposes, we can predict that low-priced coins are more suitable for purchases, especially for long-term investment, this strategy can be applied. For example, MATIC, DOT, CHZ and RNV, which started low, seem to be suitable for high volume and short-term investments.
You got good taste here, especially for Polkadot (DOT). But please be aware not all low-priced coins are good or worth buying since there are a lot of things that need to consider.
For me, there are really lof of quality projects for altcoins these days, especially if it is about NFT and DeFi, but I am more bullish on DeFi since TVL (total value locked) for DeFi is continue to increase regardless of how the market is dumping sometimes.