The best replacement for 2.4g is 5g.

The best alternatives to 2.4g are rated as following:
★★★★★  5g
★  5g network
  5g wifi
  5g routers
  5g wireless

Your alternative for 2.4g is not listed? Suggest!

No companions for 2.4g have been suggested so far.
You have in mind a companion for 2.4g and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of 2.4g in all years. Click on graph for more.
5g network