Send baby villagers through flowing water into soul sand elevator

Solution 1:

By using a cobblestone wall (you can also use a fence), the baby villager can get pushed into the bubble column.

Make sure the water stream is 3 blocks or less. If you make it longer, like this, it will not work:

Solution 2:

A simple fix would be to block the source blocks from flowing with signs. There are more advanced methods as well, showcased in the vides by Wattles and ike. My preference lies with the fencepost method in ike's video, which he starts building at 1:30.

Here it is showcased by Wattle:

Here it is showcased by ike:

Solution 3:

A solution to solve your problem would be to instead have the baby villagers path directly into the soul sand elevator.

All the beds are still pathable to the baby villagers.