In general, it seems that triops + plants don't mix, but I think I've found
something that could work for everyone.

None of my plants are potted, so what I do is I buy glass "gems" - I think they
all come in a standard size - and surround the plant and the roots with the
gems. Typically, these gems are too heavy for the triops to move. So I make
sure to cover the base of the plants with them as well as use them to anchor the
roots for the floating plants, like a water onion, all while making a wall too
heavy for the triops to move.

Make sure you press them in tight though, make sure that if the triops dig
around the gems that they don't move and get displaced.

My setup:
I only have triops L. and I have a mixture of small gravel and the above
described gems in my 3 gallon/ ~11.5 liter aquarium.

I hope this helps anyone interested!
Likewise, if anyone has any suggestions and tips relating to this issue, I'd
love to hear it!

For the American's out there, Happy 4th of July!!!