Intellij Python not able to find decimal package only _decimal

[tool.poetry]
name = "tst"
version = "0.1.0"
description = ""
authors = ["testing <me@test.com>"]
readme = "README.md"

[tool.poetry.dependencies]
python = "^3.10"


[build-system]
requires = ["poetry-core"]
build-backend = "poetry.core.masonry.api"

I use poetry init to create the project, poetry install to install the venv (in a directory .venv in the project root) and then I open the folder in IntelliJ 

IntelliJ IDEA 2022.3.2 (Ultimate Edition)
Build #IU-223.8617.56, built on January 26, 2023
Subscription is active until February 12, 2023.
Runtime version: 17.0.5+1-b653.25 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Linux 5.15.0-58-generic
GC: G1 Young Generation, G1 Old Generation
Memory: 2048M
Cores: 8
Non-Bundled Plugins:
    org.intellij.plugins.hcl (223.8214.6)
    org.rust.lang (0.4.187.5175-223)
    com.github.copilot (1.2.2.2371)
    name.kropp.intellij.makefile (223.8214.6)
    Pythonid (223.8617.56)
    com.uriyyo.evaluate_async_code (1.22)

Kotlin: 223-1.8.0-release-345-IJ8617.56
Current Desktop: ubuntu:GNOME

After opening the project I go to "Project Structure" and add a new Poetry SDK from the `.venv` folder in the project root.

Finally, I create a file `tst.py` type in `Decimal` and then Alt+Enter to auto-import, which looks like this:

I am expecting to see an entry for `decimal.Decimal` which is part of the core library which exists inside the External Libraries:

...

I assume this is something wrong with my setup as this has worked on previous machines till now, any help would be really appreciated as it's really annoying as it's happened with some other libraries as well.