You can DIY one with fine netting & aluminum profile. My previous tank was braceless & you just need to make the size the aluminum profileto sit on the edges.
Aluminum profile - get from prestech.com.sg
Netting - Can get the thicker clear type from https://aquariumoverload.com/pages/clear-mesh-aquarium-tops
Alternatively, the type i'm using is a very fine black one which i think works better than a thick clear type. I have some spare to that I can sell. Can PM me if keen.