It looks like your cabal version is too old.
You can make sure you have the right one if you first start a nix-shell at the top-level directory of the plutus-repository, then cd to the code folder of the plutus-pioneer-program-repository and run cabal build from within that nix-shell.
1.30.1 release note: All SPOs and node users must update to this (or a later) version prior to the HF to Alonzo PV 6, or risk not being able to sync to the network.
IMPORTANT: As usual, don’t forget to backup your nodes before starting these updates.
STEP 1 - Clone the latest source and checkout the branch 1.30.1
git clone https://github.com/...
WSL is a hack for running Linux programs. Plutus Playground is very stable once it is installed on a stable platform. I had hosted a playground without any issue for more than a month that too without restart. It is highly recommended that Ubuntu or other Linux OS be used as a base platform than Windows.
I'm sure there are many reasons why this might happen, but my last experience of this on Ubuntu (Pop OS) was when I was connected to a VPN. Disconnecting immediately solved the problem, so it's possible if you use a company VPN that the network traffic is being blocked for the wallet.