In terms of pure stats, Aradia actually has to stack up on good deeds to power up whereas Othinus can unleash her power instantly without any need for preperation and keep on doing it constantly for billions of years. There's also the fact that the casual firepower thrown around by Othinus far outclass anything the regular Transcendents have shown outside statements.
In terms of equipment and magic, she has no defences that might allowed her to counter either the Spiritual Items used by Othinus such as her Crossbow and Gugnir or any of the more hax spells that Othinus can casually and instantly use such as her Time-Stop, her Phase Manipulation, her Fairy Stake, etc...
In terms of endurance, Transcendents canonically died to Othinus nuking the universe whereas a fight between two Magic Gods always ends in a statement. Moreover, Othinus is eternal and immortal who can fight for billions of years, whereas Aradia is mortal with no hax defences to speak of.
In short, Aradia is outclassed in terms of power, stamina, magic, equipment, and even mindset. In fact, I can't think of any parameter in which she can compare to Othinus other than having bigger breasts.
Othinus swings her lance and it's GG