This article is nearly two years old, but provides a good overview of the latest techniques devised for achieving scalability in public blockchains:
https://polynya.medium.com/rollups-data-availability-layers-...
Since then, layer 2s (which are the principal execution layer of the modular blockchain stack the article above expounds upon) have seen exponential growth in adoption, and mounting innovations bringing them progressively closer to their theoretical potential of 100,000 transactions per second: