One happy coincide is that you can almost fill that void with chatgpt :p it's a fairly competent reddit thread simulator (not too surprising giving reddit is part of its training data)

Some of the only data we have is total downloads on the play store, of which official reddit is 100 mil+

And an aggregate of third party apps are 15 mil+ (Apollo 5, Rif 5, boost 1 relay 1, sync 1, and a number of equal or smaller apps and pro/paid editions)

Unsure about iOS numbers and website

These numbers have so many caviats that theyre almost useless

But they could give a rough estimate of ~20% given some assumption

1. Anyone using third party also downloaded official at some point
2. Third party has higher retention, due to the official app being where new redditors most likely start while third party most likely gets "new" users that already used reddit a while

Careful, your æøå is spilling out :p

And I'm coming from a surprisingly similar place, replace relay with boost and and I'd have thought you were stalking me