Lawn/patio edging

[Goawaytina]

Hello,

We have wooden sleepers holding our lawn back from the patio, about 6 inches high. These are totally rotten and need replacing.

I'm torn between replacing like for like or something different, maybe a brick wall, rendered wall or? but I'm really struggling for inspiration. I can't really find what I'm looking for in the internet, most seem a lot higher than my lawn/patio height difference.

if anyone has similar it would be great to see some ideas
Thank you!!

How about content steel. Everedge is great but I am not sure if they make any the height you need.

I just had to Google that to be honest. I think it could work if I can get the right height. More research needed but do you happen to now how far it has to to be set into the ground?