[sottol]

The probably current best solution are "dueling toolheads" or IDEX where you basically have two gantries [1] or toolchangers [2,3].

Both trade-off less waste for substantially added cost and complexity.

[1] https://github.com/zruncho3d/DuelingZero

[2] https://www.youtube.com/watch?v=1WqDcpxC3-o, https://github.com/ankurv2k6/wp-daksh-toolchanger

[3] https://www.prusa3d.com/product/original-prusa-xl-2/, https://www.youtube.com/watch?v=v3sSR2QvUyA

[plumeria]

The Swapper3D is another toolchanger approach that eliminates filament waste (and requires less print time) by swapping nozzles [0]

[0] https://www.youtube.com/watch?v=olXqJadb6BM