There are many different options, and you may want to choose different ones for specific different rooms or fittings.
First, with regard to relays, there are a number of in wall Z wave micros that can work very well to control current, but you would not combine those with a smart bulb. As you noted, the smart bulbs should always be on power. If you regularly cut power to it, you can significantly reduce the life of the bulb because of the effect of the inrush current on the radio each time you power it on again. So if you use the in wall micros, you use them with dumb bulbs.
@anon36505037 , Who lives in the UK, has done his whole house this way and can give you more advice on that option. There are a number of other members who can add more as well, this is a very popular option for the EU.
Alternatively, there are a number of different ways to handle offering a switch option for smart bulbs. Phillips hue makes their own switch which works well. Remotec has a small eight button panel, battery operated, where each button can accept tap, double tap, or long hold, giving you 24 different control options.
And many people like using a Wi-Fi mobile phone as a wall mount control center, typically with the very popular SmartTiles dashboard, which can be customized in terms of both devices displayed and the color and size of the tiles.
Of course all of these options require blocking off the existing switches so that people don’t try to use them. So if you do want to keep your existing switches, then the relays with dumb bulbs are a better way to go. Here is the FAQ for switches to be used with smart bulbs.
Different solutions will work for different people, but those are the two main directions.