I would like there to be a new subcommand, such as /sgjourney translocate <dimension>.
This would perform the same functionality triggered by walking through an active stargate by default, teleporting the player that triggered it to the desired dimension. If a stargate cannot be found, then it picks a safe location near 0x 0z.

Interacting with the stargate to move between planets is fun, but does get annoying when having to do it a lot while testing things.

Making it connect to Stargates would require reprogramming the Stargate Network entirely, since everything is based on the assumption that you're working with Stargates.

Just use /execute in <dimension> run tp @p ~ ~ ~

I didn't know you could do /execute in . Or I forgot.