Since my bikes are older, and 3 of the 4 were frame up builds, and have been upgraded over the years there are a number of choices.

Probably the best was an overall drivetrain change in going from a double crankset to a triple on my road bike and installing mtb derailleurs with a wider range freewheel.

It basically gave me the same as the double and added a climbing inner ring. I have since swapped out the wheelset with a cassette, but the foundation was already there.

John