Better Conduit Placement is a minimalistic configurable mod which allows the placement conduits in front of players, placing prismarine blocks by clicking the conduit and other tweaks.
You may also be interested in Better Beacon Placement.
All available config options:
breakConduitBlocks default true
If enabled, drops all conduit blocks when the conduit itself is broken.
dropReplacedBlockTopConduit default true
If enabled, when prismarine replaces a normal block that block is dropped on top of the conduit.
You can place blocks anywhere in front of you in the water, and click the conduit with any conduit block:

Place a full conduit beacon almost instantly anywhere by holding the crouch button:

When the conduit has the full amount of blocks around it, water will replace the other non-conduit blocks around:

You may freely use this mod in any modpack, as long as the download remains hosted within the CurseForge or Modrinth ecosystem.
Serilum.com contains an overview and more information on all mods available.
Comments are disabled as I'm unable to keep track of them across so many separate mod pages.
For issues, ideas, suggestions or anything else there is the Github repo. Thanks!