Yeah, keep telling yourself that….
Personally, I hate plastic lattice, but I hate real lattice even more. It always looks great when you put it up, but the real lattice just comes apart too quickly, too often, and in too many ways. I bet you that would be even worse with a couple giant dogs and some little kids. Once you paint the plastic, nobody will ever notice.
Are you using 4 x 4 posts? I had the thought that you could route a channel in the sides of the posts, and then flex the lattice and pop it into that slot. Then you can hold it in place with a few screws from the back.
And I have two thoughts on this. One is to cut your slot 3/4 of an inch from the back of the 4 x 4 posts, and where you need a little resistance from somebody leaning against it or the dogs jumping at it, run a 1 x 2 or a 1 x 3 or whatever, side to side behind the lattice. Paint that 1x green or brown or black, and it will disappear behind the lattice.
The other thought I had was similar. Route the 4 x 4, but instead of routing it down the side, route it down the back corner, just enough for the lattice to sit flush from the back. Then put a few screws in it, and put some kind of cross bracing across it, so it has some strength.
That crossbracing could also be something like EMT conduit with the ends flattened, or a little piece of channel, or whatever. One of my personal favorites is always free, old bed frames….
Hope it helps