I take wading footwear seriously.
For me its the simms freestones, but that is not what you are asking for.
If I were backpacking, I would probably do something similar to what you are already doing and consider a folding wading staff or invest in a trekking pole to serve as double duty. Another option…limit your wading. On a backpacking trip, wading in the water creates higher risk of injury no matter the footwear.
These days all my wading boots are outfitted with carbide spikes called grip studs. They are made for dirtbikes and snowmobiles and are the best value for the money. I have a pair of vibram freestones outfitted with them that are on their fourth season in the saltwater environment…no wear on the spikes. On my freshwater boots I have the 1300s, which are a shorter spike and a shorter auger. They make all sizes.
you could outfit your sandals with them or any spike for that matter. I cannot say enough about this brand though. I have tried several, and this is the only one that gets the nod for me. The fact that they have lasted for 4 years and probably have at least 4 more in them is just insane for any product.
One thing to note…the auger screw is much more robust than the other spikes that have just sheet metal screw threading. Even so, there is always potential of tear out in wading footwear that has a softer…sneaker type rubber. Simms wading boots are made to accept spikes. If you put spikes in your tevas, you will be experimenting. There is always a chance of push through or spikes leaning over. Even with the simms, I fit each spike with a 1/4" ID washer. this prevents installing them too deep, lean over, and push through.
Spikes are not stealthy for fish, nor do they make the stream environment 100% safe. But they are safer for the angler for sure. I recently got a new pair of boots and fished them without spikes. All i can say the difference is night and day.
I hope it helps and if you need more info, let me know.