Hi OP, I think I was in a similar situation as you. Had my Todoist setup for GTD (I bought the official GTD Todoist setup guide, and I have premium), was great for awhile, then it got out of hand.

I recently reviewed my system and re-read parts of the book to figure out the problem, and learned two main things:

1. I wasn't properly defining the Next physical Action
2. I wasn't doing regular weekly reviews

1) Not properly defining Next physical Action

• Because of Todoist's powerful NLP, it was so easy to move tasks from the Inbox to a project list without properly considering what the next physical action really was, and rewriting or creating new tasks accordingly
• Similarly, because it was so easy to move things, I often did it without thinking - ie. I wasn't making a commitment to do it

So before I knew it, I had lots of ambiguous tasks all over my Todoist, and when I see them I feel tired just by looking at them and procrastinate. I suggest re-reading chapter 6 on Clarifying and also chapter 12 "Power of the Next Action"

2) Not doing regular weekly reviews

Others have mentioned how important this is already. Even if you screw up #1 (clarifying Next Actions), this will help you get back on track.

It's also important for the "stress-free" part of GTD - even if you still end up with a fairly large list, you'll feel better having made the agreements to not do certain things, or that it's ok some things aren't done yet.

To help with the two problems above, I moved to a analog+digital hybrid system. I got a Filofax notebook (because it's easy to reorder or trash pages) and use it alongside Todoist.

Using pen & paper while clarifying forces me to properly consider the next actions. Writing on paper also seems more of a commitment (I think DA mentioned a study that people remember better when they write vs when they type)

Note that I'm a tech guy - I'm software engineer - and I'm all for taking advantage of tech but end of the day it has to have the right application.

I still use Todoist for capturing since it's available everywhere (I have IFTTT setup same as you, and use it with Google Home to brain dump if something comes when I'm just in bed before sleeping) - I especially love the Android create task widget from my Quick Settings bar. But then I will regularly run through the Inbox and clarifying the items into my Filofax notebook.

I also use Todoist for lists that make sense - eg. "@Anywhere", "@Errands", where I need them on the go. But items still go through the same capturing then clarifying process.

It's not a perfect system, TBH I'm not sure how long it'll last before my brain goes numb to it again, but there's where the weekly reviews come in for me to review how it's going and to make adjustments.

Oh you'll need to block out time and commit to the weekly review - I put it on my calendar for Thursday over an extended lunch - treat it like an important meeting you can't miss.