Using this script you can create a tiny macOS app that will always launch the latest version of any JetBrains Toolbox installed IDE. Simply pass the target IDE application as the first argument and the script will create a launcher that you can add to your dock that will always point to the latest installed version of the IDE.

make_launcher.sh

#!/bin/bash

APP_DIR=$1
APP_SCRIPT_NAME="$(ls "${APP_DIR}/Contents/MacOS/")"
APP_FILE_NAME="$(basename "${APP_DIR}")"

CHANNEL_DIR="$(dirname "$(dirname "$1")")"
CHANNEL_NAME="$(basename "$CHANNEL_DIR")"
TOOLBOX_APP_NAME="$(basename "$(dirname "$CHANNEL_DIR")")"

TOOLBOX_DIR=${APP_DIR%/apps/*}
LAUNCHERS_DIR="${TOOLBOX_DIR}/launchers"
if [ ! -d "${LAUNCHERS_DIR}" ];then
  echo Creating launcher directory: ${LAUNCHERS_DIR}
  mkdir -p "${LAUNCHERS_DIR}"
fi

LAUNCHER_PATH="${LAUNCHERS_DIR}/${APP_FILE_NAME}"
if [ -d "${LAUNCHER_PATH}" ];then
  echo Launcher already exists at path ${LAUNCHER_PATH}
  echo exiting.
  exit 1
fi

# Create the launcher directory structure
echo Creating launcher at path: ${LAUNCHER_PATH}
mkdir -p "$LAUNCHER_PATH/Contents/MacOS"

# Link the existing
ln -s -f "$APP_DIR/Contents/Info.plist" "$LAUNCHER_PATH/Contents/Info.plist"
ln -s -f "$APP_DIR/Contents/Resources" "$LAUNCHER_PATH/Contents/Resources"

LAUNCHER_SCRIPT_PATH="$LAUNCHER_PATH/Contents/MacOS/$APP_SCRIPT_NAME"
function write() {
  echo "$1" >> "$LAUNCHER_SCRIPT_PATH"
}

write '#!/bin/sh'
write ''
write 'DIR="$(dirname "$0")"'
write 'BASE_DIR="$DIR/../../../../apps/'"$TOOLBOX_APP_NAME"'/'"$CHANNEL_NAME"'"'
write 'SUFFIX="Contents/MacOS/'"$APP_SCRIPT_NAME"'"'
write ''
write 'release_dirname=$(ls "$BASE_DIR" | sort -r | head -n 1)'
write 'release_dir="$BASE_DIR/$release_dirname"'
write ''
write 'app_dir="$release_dir/'"$APP_FILE_NAME"'"'
write 'app_path="$app_dir/$SUFFIX"'
write ''
write '# Make sure the info.plist and resources are current.'
write 'ln -s -f "$app_dir/Contents/Info.plist" "$DIR/../Info.plist"'
write 'ln -s -f "$app_dir/Contents/Resources" "$DIR/../Resources"'
write ''
write '"$app_path"'

echo Making launcher script executable...
chmod +x "$LAUNCHER_SCRIPT_PATH"

echo Successfully created launcher for $APP_FILE_NAME in channel $CHANNEL_NAME
open "$LAUNCHERS_DIR"

Thanks!
EDIT: seems like PyCharm does not see environment variables, like PATH, when launched this way
Deleting JetBrains Toolbox and launching PyCharm directly still seems like the best solution