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Depending on how much work you want: Thyme is low and pink flowering (needs sun/draining soil), lavender is herb-ish (the white / pink ones don't do as well according to my mum but they exist if you want a non purple one), sage/chives also do wee flowers.
After that you end up with annuals and more work.
A rosemary becomes a big shrub/bay trees so not really a bedding thing anymore. Mint is easy to grow but rather...invasive.
That's a pretty big front garden! Lots of options :)
Ajuga/Heuchera are don't grow tall and have coloured winter leaves/flowers.
For summer Geranium have a lot of colours to pick from and there are many groundcover ones, they do go brown in winter I think.
Maybe that works?