That bed look very big which means you will have to step in to reach the middle and compact your soil mix in the process. If you can create a walk way in the middle by adding another row of blocks it would help.

A good idea is to use "lattice vinyl" as fencing which should be easy to get. (example) To secure them is tricky in this case, but you can drive 2x2" wood stakes into each corners, and power drill the vinyl panels onto the stakes. If that is too expensive you buy a roll of durable plastic netting.

You can also double stack the concrete blocks and add another layer, which is what I do. Or you can just plant flowers or something in each of the holes.

I drive rebars into each corners of my concrete raised bed, then put on conduit pipes to make trellises. In this case you can drive in those T-posts into 3 corners of the bed, which makes two
trellises, in the direction that you feel will give most direct sunlight and not shade the rest of the bed.

Edging inside or outside the bed? I wouldn't use any sort of live plant edging personally given the invasive nature and access problems they create. But given your goals, would use some sort of low decorative fencing as Max mentioned.

Agree that you are going to be sacrificing some of the grow space to paths given the width so you might as well incorporate some pavers into the design now. Is the bed only 1 block deep or did you till up the ground underneath it first?

Dave

I don't know if you have gophers where you live but here in bay area we have a gopher invasion so my raised bed (very similar ) bottom is lined with hardware wire and two rows of blocks high (your back will thank you) I also use rebars to keep blocks in place. In the block holes I fill with potting soil and compost and plant the holes with herbs, parsley, oregano, scallions , tarragon and some of the holes I even planted bush beans and strawberries for my grand daughter to pick