First, stop playing 4* maps. You can't even finish those, and yes, spamming hard maps and effectively spazzing out in an attempt to pass them isn't going to help you. You won't have any rhythm sense built up, nor the ability to read the patterns that you see.
Second, don't play with mods. They can be fun, don't get me wrong, but you don't need to worry about how Hard Rock (HR) ups the Approach Rate (AR, or how much time you have between the notes appearing and you needing to hit them; the higher the AR, the less time you have to react), overall difficulty (OD, or the timing window to hit each note perfectly; the higher the OD, the more precise your keypresses have to be), circle size (CS, also fairly self-explanatory; the thing you gotta remember is the higher the CS number, the smaller the circle, and yes it can get smaller than the cursor), and vertically inverts the entire map (a circle at the bottom right without will be in the top right with). DT speeds up the map by 1.5x, which already can throw off your rhythm sense and affect how you hear the music, so that's definitely not what you want when you're starting out; it does also affect AR and OD due to the speed up. And Hidden removes the approach circles as well as hides the notes within a certain timing of needing to hit the note. Like I said, they can be fun, and they are challenging, but for a 7-digit like you they are detrimental to your growth starting out.
Based on the fact that you have A-ranks on some basic Normal (2*) maps, you should start in the mid-high 1* range, possibly between 1.6 and 1.9*. Your first goals are to practice your rhythm sense and reading the notes. Rhythm sense is basically learning how to tap the notes to the beat of the music, or to whatever rhythm the mapper decided to focus on. You want to be able to listen to the song in question and hear the beats and rhythm and know "okay, the map is putting objects at every full measure (eg. 1/note-2-3-4-1/note-2-3-4), so I can listen for that or just count it out to myself", for instance. That will help you grasp the flow of the song in a rhythmic sense, which will aid you greatly when you get to maps that switch up not only the bpm of the map but also what instrument they're mapping to. DT hampers this because of the speed-up. The general rhythm is mostly the same, sure, and it may not be as noticeable in the 1* range where the object density is still low, but even in the 2* range there's a big difference in how you have to listen and play.
Note reading is being able to see what notes are coming up next and knowing how to move your mouse/stylus to each one accordingly. You really won't get very fair just flailing your mouse whenever you see a circle appear in you periphery, as you're not anticipating where the note is to play it in time with the rhythm but just reactively aiming whenever you see something. Hard Rock makes this worse because you not only have to remember the notes are flipped, but if the AR gets high enough (like AR9 or so; possibly even AR7 for you at this stage) it's less about seeing and moving and more akin to trying to catch a fly buzzing around your screen. YOu see it for a moment, but by the time you clap your hands there (or move your mouse over, it's already gone).
You'll know you've got these things down when you can consistently get over 95% on any map you download. I would say 90% or so is a low minimum you can start with, but you really want to get up to over 95-97% most if not all of the time, with S-ranks and/or FCs to boot. Once you get to that level, then you can move up the star rating into the low 2* range and repeat the process again. I usually suggest doing this in increments of .2-.4*, but if that's too fast or too slow you're welcome to change it up as needed.
One thing that will help you last in playing is to find songs (and later, mapping styles) that you like. Currently your focus should be on building up your fundamentals to play harder songs, but once you've got that down and you don't need to worry about that as much, you can see what kinds of things suit you. Maybe you'll find HR is still cool, or DT; I would wait until you can play 4*'s before seriously going back to using mods, but again, you do you in that case.