Kill a wyrmling dragon
Fizban's Treasury of Dragons includes the following draconic gift (p. 28):
Draconic Familiar
Draconic Gift, Uncommon
You gain the aid of a draconic familiar, which might be a splinter of the consciousness of a dragon that invested you with power.
You can cast the find familiar spell as a ritual without using any material components. When you cast the spell in this way, your familiar always takes the form of a pseudodragon.
Uncommon draconic gifts can be won from killing a wyrmling dragon. A white dragon wyrmling, for example, is CR2 - a very risky and deadly fight for a level 1 party, due to the breath weapon, but winnable with a bit of luck and preparation. (How you deal with the enraged parents is another story — best leave no tracks and make sure to leave the scene fast and far).
Of course, you then also need to work with your DM and have your DM play along and have this be the transfer of power draconic gift effect. But it's an official rules based way to get this spell on level one for a martial, it is not based on just pandering to the DM for a gratuitous handout - you will have earned it. So, become a dragonslayer.
(Or, as @TreeSpawned points out, the dragon can also bestow this gift to their chosen heir (p. 27) so with DM support, this could be part of your backstory).