Last thing though- glue barely barely pushes through a 14 gauge needle (air gun nails and needles are roughly the same size) so test it first it’s not as easy to suck up glue and push it through a syringe and through a needle as it looks trust me
So I tried the above method using a syringe and carpenter glue.
The clear pvc tube that came with the syringe was useless since it was too flexible and it wont go deep enough under the floor
I have used the feed pipe (the one in the bottle) from an use Ants Out spray and that fit on the syringe and it was strong enough to be pushed under the floor.
Pushing the glue through the syringe required some force but it worked.
I managed to push a good amount of adhesive there and when it was all it I used an air compressor to push it further.
That worked too to a degree ..I can't say how much
Then I used my bench drill, some gym weights, two Home Depot buckets full of water and the counter weights that I have recycled from a laundry dryer.
Here are the final results
-I should have used more weights as there is stull I small bump in the floor where the two boards connect to each other -you can feel it only if you are bare foot or with a level. There was no way to push against the ceiling to compress those boards more instead of adding weights as the ceiling is fragile in that area. After applying these weights some glue got pushed out back from where it came from, which means that at least at that end I had more than enough glue
-the glue went in properly but not far enough the secure both ends so the far end away from the end used to push adhesive is a little bit lose but I think some super glue at that end will fix this