The phrase "acknowledge that indeed" is correct and usable in written English.
It can be used when you want to emphasize the recognition of a fact or truth that is being stated.
Example: "In our discussions, we must acknowledge that indeed, the challenges we face are significant and require immediate attention."
Alternatives: "recognize that truly" or "admit that certainly".
However, we acknowledge that, indeed, some developing countries (e.g. Cuba, Venezuela, China, Thailand, Philippines, India, Egypt, Senegal, Ghana, etc).
An honest answer must acknowledge that indeed some progress was made: roads are being repaired or asphalted.
It isn't that girls are weak, it isn't that boys don't know better, it is simply that men and women are not working hard enough to acknowledge that we indeed have a problem of rape culture and it isn't going to stop by itself.
So let me acknowledge that there is, indeed, a gay agenda.
But they did acknowledge that North Korea had indeed dabbled in nuclear fusion research.
The Darwinian response in this case is to acknowledge that there are indeed examples in nature of features that have no function or of features that are not optimally adapted to serve the function they apparently have.
Del Bosque did acknowledge that he had indeed already selected his team to face Ireland, but insisted on keeping it a secret despite repeated attempts by journalists to coax it out of him.
In online communities, we can acknowledge that drinking is, indeed, one way to cope with a hard day of motherhood but that deep breathing, tea and good conversation also work.
Hence the need to think beyond traditional assistance and to acknowledge that countries are indeed developing and economies are growing.
Only belatedly in his 2004 book, My Prison Without Bars, did he acknowledge that he had indeed bet on baseball games.
Then, we have to acknowledge that we do indeed know just what destination we mean, that we know what healthy living looks like.
