I want to make a Rock Gnome Artificer (from Unearthed Arcana) but there is something I'm not happy about with the character I'm planning.
Rock Gnomes (PHB, p. 37) get proficiency with Tinker's Tools:
Tinker. You have proficiency with artisan's tools (tinker's tools) ...
Artificers (p. 2) get to pick two tool proficiencies:
Tools: Thieves' tools, two other tools of your choice
and may get more proficiencies from other class features, for example (p. 6):
When you choose this specialization at 1st level, you gain proficiency with smith's tools ...
My problem is this Artificer feature (p. 3):
Starting at 2nd level, your proficiency bonus is doubled for any ability check you make that uses any of the tool proficiencies you gain from this class.
Since I got my proficiency with tinker's tools via the Rock Gnome racial trait Tinker, rather than from the Artificer class, this means I do not get to double my proficiency with tinker's tools, since Tool Expertise only allows you to double your proficiency with tools gained from this class.
To my mind, an Artificer (or at least, a Gunsmith Artificer, which is the archetype I'm going with) would be good with tinker's tools, since it fits with the flavour of the mechanical theme, such as the Mechanical Servant feature (p. 4). Rock Gnomes are also naturally good with tinker's tools (as their description in the PHB makes clear). So it would stand to reason that a Rock Gnome Artificer should be extra good with Tinker's Tools. Or at the very least, I want mine to be.
But as it stands, a Rock Gnome Artificer will always be worse with tinker's tools than any other Artificer (who picked tinker's tools as a chosen tool proficiency), which annoys me. I'm not going to ask why this was worded in this way, or why Artificers don't all get proficiency with tinker's tools for free or anything else like that; this is not a designer-reasons question.
Instead, I want to know if there's any other way for my Rock Gnome Artificer to have double proficiency with tinker's tools. For example, can I just take the same tool proficiency again via Artificer, even though I already have it via the Rock Gnome's Tinker racial trait, so that I qualify for Tool Expertise? I'd even be happy with a way that doesn't involve Tool Expertise at all.
Is there a way for a Rock Gnome Artificer to have double proficiency with Tinker's Tools? Besides the DM saying "screw it, you just do because I say so". Anything official or UA is fine, but no homebrew or DM fiat. Also I'd prefer no multiclassing, but if an answer mentions it alongside other potential solutions for completeness, I won't complain.