Always go bigger with garden borders. What looks large with bare earth ends up tiny when full of shrubs and bedding plants. I see meters so uk?

And post photos for better help…

Yes, pictures would be good. 70 cm is too narrow to be of use for anything more than annuals or small perennials. If you want roses they'd need to be minis or patios.

i think I can envisage what you have. I’d Google ideas for ‘small front gardens.‘ To behonest three beds around the sides is rather an uninspiring design.

IMO, what's in the beds matters more than if they are around the edges or not. If OP is in the UK, the lawn's probably small.

I'm biased because what the OP seems to be describing is is a small front garden that uses the 'negative space' principle - and that is what my garden is based on too, although probably a bigger space than what the OP is working with... In this context 'negative space' is the space that is not planted with perennials, trees, or shrubs - i.e. the lawn is the negative space. Shaping that space makes a dramatic contrast to the planted space. The OP's planned beds, though, do sound too small - but it would make sense to do a scale drawing to see what dimensions are pleasing. Right-angled corners to the lawn are most appropriate in a 'modern' style design while rounded corners suit a more 'casual' design. That's what we used - which also make it easier for dogs to run the paths! I'm not sure if the pictures below of what we did here will be useful or not but I think they show the effect of 'negative space' in the garden. The pictures (and plan drawing) are from various periods and some things changed from the plan to current reality....

The overall plan:

Two 2022 views of the rectangular lawn in the backyard:

IMO shaping the OP's front garden with the 'negative space' idea in mind is well worth considering as it works well in any size of space and can be very striking I think.