How to start a venv on startup and run a program on Raspberry Pi?

Use systemd. You don’t “activate” a venv at boot; you simply run the venv’s Python on Raspberry Pi directly. 1) Create your venv (once) mkdir -p /home/pi/myapp cd /home/pi/myapp python3 -m venv .venv source .venv/bin/activate pip install -U pip pip ...