There are 23 different Miracles to learn. While it is possible to complete the relative task early in Cycle 2, it is not recommended to do if you wish to cut excessive game play time, as short as just a little bit to venture into Cycle 3, for attaining all Dark Souls' Trophies/Achievements.
This is because you require the Dark Lord's Soul two times, and the effort of events for being able to offer that Soul at the Sunlight Altar early in a Cycle, are relatively minimalistic compared to those necessary for relative weapon modification by using that Soul. If you agree with that, you shall let that relative weapon being created in your initial Cycle in Lordran. Lastly, offer the next acquired Dark Lord's Soul to the Sunlight Altar to obtain a one of a kind Miracle.
You will require only 10 Sunlight Medals to achieve Rank +1 of this Covenant which one you will discover there. The ultimate strategy to work on this is, to be in this Covenant and let yourself being summoned as a Golden Phantom for standing aside in battles of fellow lost Undead Humans - when a Boss is defeated under this condition, all Players will be rewarded with one Sunlight Medal. Also, the eight standard Chaos Bugs can drop Sunlight Medals. Sunlight Medals are also positive for being available for pick-up when a Player drops any. I have about 150+ spare Sunlight Medals - and I kept my Character's Soul Level at 50. I can eventually spare some, because I do not require that many, but you must eventually complete some assists anyway, hence this decreases the required value of Faith related to be able to complete this particular task for obtaining the relative Miracle. To maximize efficiency of your investment on Sunlight Medals, you shall only ever offer ten Sunlight Medals to the Sunlight Altar if you have the Dark Lord's Soul and you intend to offer this one in the same Covenant progression. That way, you will acquire two different Miracles during the same event. Please note that there are three Miracles to obtain from the relative Covenant, not two.
The other 20 different Miracles are surely obtained by you during your initial Cycle, if you make the right choices at the right moments during game play. Please consult the Dark Souls Wiki to get relative very important information, before you continue to progress further in your adventure. If you failed in any of those relative tasks to positively affect the game play for the required outcomes to be achieved during your initial Cycle, do not feel pity, because you can do it right during Cycle 2 for sure, as you anyway want to achieve all records for this excellent title.