Underwater Grass Blocks

In 20w12a you fixed bug MC-130137 (Grass and mycelium don't decay underwater).
It is a good fix but it ruins some good designs.
Of course we can have seagrass but having normal grass blocks also looks good. And sometimes it even looks better.
So my idea, probably a request, is to add a way to place grass blocks underwater in a way so they don't decay.
At first I thought about a separate gamerule but that is too much. I also think that it should be accessible in survival without commands. So maybe they should be placed on a specific block. Maybe glowstone or prismarine.
I am bad at making ideas. I just want some really good designs to stay available.
And I understand that randomTickSpeed 0 will do this. But 1. It is a command, and 2. It disables too much in survival.

I am a bit late with this request but there were some more important things in life.