From your screen shot, it does not show any tabs in the first 1.5" or so. Do you have any tab stops set at all?
I played around and as long as the very top of my screen cursor was on top of the "T", I didn't have much problem with dragging around the indent icon. Too low or high and you create a new tab stop. Unfortunately, macOS does not give any feedback when you are in the correct position to move the indent marker or are just creating a new tab stop.
Perhaps you could use tabs to indent your text rather than use the "indent" marker to do it?
Also, are you using a mouse or a trackpad or what to move the screen cursor? Another possibility is using the zoom feature in macOS -- open the System Preferences and then Accessibility and then click on "Zoom" -- is the "Use scroll gesture with modifier keys to zoom" checkbox enabled? If not, try to check it and then use whatever key was specified (I use Option) and then hold that key down and use the scroll feature of your "mouse" to zoom in and out to place the screen cursor tip right where you want. Then click and drag the indent icon (the "T") and you should see the "T" move as you "drag". Using this "Zoom" feature takes a bit getting used to but is very handy at times. My old eyes don't see the screen as sharply as they used to ;-)
If you're using a trackpad type device, maybe give a mouse a try -- I find a mouse a lot easier to put at a specific position on screen rather than a trackpad type device, but that is only my personal opinion.
Good luck...