Currently, there is no way that I know of to avoid being pushed by flowing water without you actively pressing any of the movement keys, even if you have Depth Strider III on your boots. Depth Strider only reduces the speed at which you get pushed by flowing water, but does not prevent it entirely on its own. To remedy this, I would like to add the following tweak:

Tweak: disableFluidPushPlayer
Alternative names: disableWaterPushPlayer, disableFlowingWaterPushPlayer, or similar
Description: If enabled and you have Depth Strider III on your boots, you do not get pushed by flowing water even if you are standing still.
Example use case: After building up the storage system, you then have to configure all of the filters. For water-based storage systems, this means you may have to go into the water streams themselves. Having this tweak enabled will save time by not having to go back to a previous filter because you skipped it due to the flowing water pushing you.