So... I've been creating five new themes (fka skins) for Ableton Live 10 for you. Some lighter, some darker, some with only some sprinkles of colour amidst the greys, others with tinted greys. Hopefully at least one that fits your needs. And if it's just a colour or two you don't like too much, you can quite easily replace it yourself (see the linked tutorial below).
Get more free themes. You can still download the Live 9 skins. If you don't know how to install them, have a look at this tutorial, and if you'd like to create your own themes, I've got a tutorial for that as well.