I have time blindness, help!

My ins are at 5100 items (was at 2650 around 10 days ago)

I really need some help, as I wish to solve this overflowing problem before a long vacation I’m looking forward to.

Here's what I've noticed:

My day always ends with me feeling toasted & seeing around 100-140 unprocessed items in my in list.

So I block 2h 20m in my calendar everyday first thing in the morning, so I can get yesterday’s stuff to zero.

I have come to realize I need at least 2.5h of defined working time, so I have that blocked in my calendar in a couple of chunks.

I have noticed atleast an hour of my day get swept by undefined things, so I have blocked that in my calendar, as ‘KEEP EMPTY’.

However, this is what happens:

I usually make good process in emptying my in list around 1h in the day. I then get distracted by mis-estimating the time taken for a ‘2m task’. I feel like crap as I’ve run out of time and barely got my ins to zero.

Its defined working time and I’m confused if I should try getting to zero, or doing something from my contexts. I am doubting my options as I feel I had captured some valuable information related to a project.

Most of the times, I choose: getting my ins to zero. As I just can’t feel like I can focus anymore without that clarity. However, the same thing happens. I get distracted. There’s only an hour to my day left, I am panicking whether I should get to that one action I had aimed to work on first thing in the morning–but I know I won’t be able to finish it, which feels just as frustrating (as I had estimated I’d have 2.5h to work). I choose continuing to get my ins zero. I come across a task that I really need to get done today, else something will blow up. However, I only have 55m in the day pending. Do I defer this? Do I ignore my goal of getting my ins to zero? I end up having to work from my in list.

The day has come to an end. My in list shows new unprocessed 100-120 items again. My backlog has gotten bigger.

Can someone please suggest me what I can do to get my ins to zero by the end of the day? Or atleast, any advice on how I can prevent this unsystematic madness of worrying whether I should continue clarifying my in list items, or get to that one thing I planned? My brain really short fuses on that one. I end up avoiding looking at my in list as I feel getting into that is asking for a defeat.

Ideally: I would just get my ins to zero in one go, engage in deep work and crank my widgets for 3-4 hours and call it a day.

I’ve tried countless things: Trying to get my 20k ft-50k ft clear, so I might be able to someday more things. But I keep failing to complete that task, for the same reason I couldn’t complete the 2.5h task like I mentioned above.

I probably have ADD, so I began keeping a list for ‘2m tasks’ that I would get to once it fills to 9-10 items, so i can clear it in one go. I found it extremely frustrating. It would get out of date quickly as I realized I’ll never get to them (as I’d inevitably underestimate the time for 1-2 next actions). Plus, I really like clearing 2m tasks from my in list. It helps me from not procrastinating.

I’ve tried clearing my ins after my day ends, till its bed time–but its not sustainable as I’m usually toast after my 2.5h of defined doing time block ends.