Microshift Advent’s medium RD officially spans 11-46T blocks for 9 speeds and is comfortably clear of the ground for highway and gentle gravel use. For more rocky terrain their Advent SS RD spans 11-38T blocks and was designed for 20” wheeled kids MTBs. Microshift Advent has a wide range of shifters and I’ve set it up on folding bikes with MTB, road and bar end shifters.

Their version 2 Advent X RD appears to have similar or slightly better clearance for a 10 speed 11-48T block and is compatible with their Sword shifters, but I haven’t tried this one to be sure about clearance.

At one point I had a folder with Advent and an 11-42T block and another folder with a used SRAM DD. I found that the DD added complexity and a degree of overlapping ratios in practice, and was an additional complexity to maintain or repair. I replaced that folder with another one with Advent and an 11-46T block.