To make the flood strat work in the past I would recommend a few things.
Don’t Tech Unphase. Esp against green your trying to make sure they don’t have a board, and they dont really have units/heros that you have to worry about sitting in the back and winning the game.
If your going to tech double Seers, you need a highier percentage of your deck to care about time runes, only having plasmodium is not great to get value from them. This is also true of Temporal Research, which you mentioned being part of your win con with R&D.
3)If your relying on an ultimate spell as your win con, teching it the turn you max the hero is too late. By the time you cycle round to it, your likely to have lost the hero as you can no longer heal them. (This one didn’t matter in this game, as Geiger never lived for a whole turn but I feel should still be made)
If you want to see my take of board spam (I generally think of it as forecast spam, but that’s my variant on it) I did a game as purple v Green here where I used it.