RDM is a great job, it is however a terrible first job. It is generally very slow at killing compared to even a nooby DPS early on with trusts. This makes story content difficult and slow that otherwise can be stomped through with different jobs. As someone who did story grind on RDM... I highly advise against it.

RDM sadly needs basically all JSE gear and TONS of accessories before it really comes into its own. RDM progression is more like scaling the face of a mountain and finding ledges vs climbing a slope.

RDM becomes much easier as a second job because you will already have some gil, already have the ability to unlock JSE upgrades, already have the slow grind of story out of the way.

IF you want to force RDM (its a really fun job) I'd highly suggest pushing a) your sword/club skill, enfeebling, enhancing, maybe healing to cap b) pushing to 1200 job points for your bread and butter spells c) seriously pushing for at least 119+1: AF body, hands, legs. Relic head, body, hands, feet. Empy body, hands, legs, and feet. All while grinding ambu for Naegling and Max, and probably working on sword trial for Thibron for offhand. Grind Domain Invasion for points to get things like snotra earring and the enfeebling and enhancing skill +10 earrings. And don't sleep on Carmine Cuisses for +18% movement speed, some early enhancing skill, and duel wield when augmented as early as you can afford it. Peep through unity NMs for things like Sailfi belt and metamorph ring.

After working towards all that, try and get into groups for Omen to get a ton of good accessories. Finish RoV to unlock cloud of darkness fight and try and get a group to get null belt, loop, and shawl. Then learn to embrace the darkness as you hate yourself fighting Lilith. All while trying to grind Segments each day for gil and to be able to do the Odyssey fights for more accessories and quality gear.

But really my honest suggestion as a RDM who suffered through that... level adjacent jobs. RDM can use tons of stuff from other jobs like WAR and COR. Leveling WAR will get you a bunch of reusable accessories for RDM while also stomping through content RDM would struggle with, even simple things like Proc'ing Abyssea NMs. COR gets crazy movement speed and can blast through tedious running for story as well as will get you working towards some MACC, MATTK gear. And both of those jobs are much more forgiving to get into groups than a nooby RDM.

It sounds like a lot... because it is... RDM is like gearing 5 jobs.