So Macros are helpful but I don’t think they are the most significant factor when it comes to making your rotation more streamlined and manageable.
Basically, most of the addons I’ve ever used have been stuff like Mouseover macros to just change how my abilities target stuff by default, or macros to include some off the GCD items and Trinket procs to certain key abilities so I don’t have to press them manually. I also often use some macros for things like setting Target Markers, or making sure my pet attacks the whatever target I’m currently attacking if I’m playing a pet class etc.
I would consider making several mouseover macros for sure as a mage, converting most of your spells into mouseover variants of themselves, and get used to using them, but other than that and maybe some trinket + arcane power combo macro for burst windows, I wouldn’t worry about them too much. You really won’t get that much more value out of them than this in general. Using one ability after another, after another isn’t really advised, but if you really want to go that route you can check out Gnome Sequencer Enhanced addon (I just learned about it today in fact and watched some youtube on it, it pretty much lets you create 1 button macros to cast multiple things in order, I’m honestly still not convinced it’s allowed by Blizz but yet, this addon has apparently been a thing for many years…)
Instead of that though, I would encourage you to check out WeakAuras and ShadowedUnitFrames and just use your abilities manually, but with a more efficient UI to help you stay focused. These essentially place all the important information in the center of your screen so you aren’t dealing with the Blizz default of putting your CD’s at the bottom, your Life and Resource bars at the top left, and your Target at the top of your screen etc. The default setup splits all the important info away from your character in the center which is where your eyes need to be the whole time and it just makes playing the game way more difficult than it needs to be.
Weakauras are particularly amazing because you can set them up to give you very helpful Visual ques as to what abilities are ready, what abilities are down, and what your priorities basically are at that moment. If you’re really so inclined, you can basically set up weakauras to detect what is on cooldown for you, and baically prompt you with an icon of the optimal ability to use next in terms of your specs priority list, it’s up to you how to program it all. Again, you should aim for not needing these priority list prompts, but I’d be lying if I said they weren’t very useful and potentially good training wheels to get you familiar with what an optimal rotation actually feels like. Once it’s muscle memory, you can turn those prompts off and start adapting on the fly.
Now with that said, Weak Auras is a very steep learning curve in how to use it, and can often feel like programming with all the “If statements” so I would only go for this if you feel ready to do so, but the rewards are amazing and it can make playing the game feel a million times better IMO, probably a far bigger help than a couple macros at least.
Basically youtube WeakAuras a bit, see how you feel about it. You can probably find some user created setups already out there that you can just import without making anything manually at all.