We use Thonny IDE for Python. You can install libraries like matplotlib, pandas, tkinter, pygame, sqlite, venv etc.
It's more than good enough for GCSEs but decent for T-Levels DPDD.
For much less work and quick demo, we use Trinket.io.
Just make sure that if students are using it for free that you use Python 3 syntax.
F-strings isn't supported on the free version.