I always hate compiling and building. It's an error-prone path filled with riddles and unknowns.

mosh is a great tool replacing ssh in many cases, Sadly it does not provide a arm64 binary download or installer for M1/M2/M3 MacBooks. Moreover I dont like XCode and protected /usr/bin and shit so I prefer isolated envs like miniconda3, so it took a bit detoure but anyway, following the official mobile-shell build wiki, type these commands:

conda install autoconf automake libprotobuf pkg-config`
git clone --depth=1 https://github.com/mobile-shell/mosh.git`
cd mosh

./autogen.sh
./configure --prefix $(conda info --base)
make
make install

And it's done. All thanks to authors for open source project and butter-smooth build scripts.