What kind of shrubs are the taller ones? Have you tried cutting them back to about a foot from the ground to see if they'd thicken and could be kept cut as a low hedge?

You'll get some responses here but are you aware that Houzz has different and more specialized forums including for gardening and landscaping?

I have no idea what they are! We had a landscaper cut them back too far and they didn't make it through the winter. I've also been told they grow up to 20 feet high.

Thanks for the input on the forums! I'll relocate my post.

That triangle of grass will be a constant maintenance problem.

some ideas

I would not remove the grass triangle and I would plant Cistus in the empty space.

If there is room in front for more I would plant Erigeron. I would not plant many varieties as it is not a large area and you did not mention wanting a perennial bed.

Can't tell if that is a traffic corner. If so, is it possible the PO might have had some functional considerations, such as reducing headlamp glare from turning vehicles?

Other than that, like how you've opened up the view and hope to see how you eventually rebuild it.