DOS is a simple operating system, and you don’t need to use an install program.
You can actually install FreeDOS the old-school way, doing every step “by hand,” like it was the 1980s. This lets you make FreeDOS as small as you want it.
General steps:
1️⃣Partition the disk with FDISK
2️⃣Create a DOS filesystem with FORMAT
3️⃣Unzip the packages to the disk