Many of the issues about bike storage and safety at bus, trains, etc have been addressed around the world. I am not sure if there is a 'best' approach but some that are used include bike lockers, bike shelters that are entered with a 'pass card' and have camera coverage. In places where I have lived in the USA, we simply had bike racks.
My approach was to purchase a very inexpensive second hand bike for my town commuting. Since town commuting is often just a few miles from home (supermarket, bus stop, restaurant, friends, etc.) most bikes that operate OK can make the ride. Commuting bicycles are built for comfort, not for speed, just like Howlin Wolf. So, if someone really wants to steal it, perhaps they really need it more than you.
Unfortunately, it sounds like racks on buses, bike lockers, bike racks at stores etc. are not popular options for most posters. In the States, it takes an incredible amount of advocacy to build awareness and action by officials. After a great deal of work, a nearby town here is getting improved bike parking with bike lockers at the train station. The plan started with a new parking lot but with the advocacy of bicycle enthusiasts, the project added the bike parking. A first for around here! Another town placed a few bike racks downtown for parking while shopping. I request my grocer, dentist, favorite restaurants, etc to buy and install a proper rack for my bicycle parking. And, in the USA now, there is a movement for Complete Streets legislation which basically says if/when a street is being installed/widened/changed, ALL users need to be considered and not just automobiles. In my state of Connecticut, they appear to be trying to implement the policy. But, this all took a great deal of work to raise awareness of elected officials.