I've been testing the installation of Plone with pip and the biggest lesson so far is to pin pip to a version lower than 20.3. This version of pip introduced backtracking for dependency resolution and it makes it close to impossible to install Plone.
The following snippet works like a charm:
python -m venv .
./bin/python -m pip install "pip==19.2.3"
./bin/pip install -U setuptools wheel
./bin/pip install Plone Paste -c https://dist.plone.org/release/5.2.4/constraints.txt
While running the following snippet will prove the case (with pip install "hanging" after downloading all packages and creating the wheels)
python -m venv .
./bin/pip install -U pip setuptools wheel
./bin/pip install Plone Paste -c https://dist.plone.org/release/5.2.4/constraints.txt