Has anyone personally cross pollinated aquatic plants?

In my honest opinion, if it was bad to hybridize plants, they wouldn't be able to.

I know there's a ton of ludwigia hybrids, they occur on their own in the wild, but some crosses have been intentional with farmed plants

Eh, I mena I guess you could but idk anyone that has grown stem plants from seed. Most plants seem to just be formed from cuttings of the same plant, meaning that a lot of different "sources" of a plant are probably genetically identical.

Also, I feel like I wouldn't hybridize Rotala's....mostly cause half of them already look the same to me lol But that's just my two cents

This is something I want to try doing but I need to the plants to grow emersed and flower.