Force alt + tab to switch only in the current workspace.
Extension Page: https://extensions.gnome.org/extension/4443/alt-tab-only-on-current-workspace
First, clone this repository.
git clone https://github.com/ermesonsampaio/app-switcher-only-on-current-workspace.git
Then, change to cloned repository and install extension.
cd app-switcher-only-on-current-workspace
chmod +x install.sh
./install.sh
If it doesn't work, restart the session.