Apartment friendly acoustic treatment options?

Howdy!

I've got a question that isn't explicitly music production oriented, but it seemed the most relevant. All my music is completely vocals-lacking so I've always shunned a mic, but now I'm working on a series of tutorial videos. Given the target audience is musicians, I want to get the audio right, and that includes my talking.

I was dabbling in mics and I've landed on the Rode Procaster as overall it seems to offer the best sound for my purposes and seemed to play the best with my room acoustics so far. My problem now though is that I do still get a little (tiny, maybe imperceptibly to everyone but me) echo in my recordings, and I know that is easier to clean up before it gets into the recording.

The room I'm in is an apartment bedroom (well technically it's set up as an office, but I digress) about 10'x10' in dimensions. I have desks and a bookshelf in there, but otherwise the walls are fairly bare. Given it's an apartment I can't really glue stuff to the walls.

What would be some suggestions for addressing this? Right now I'm considering either putting some foam up using some thumb tacks, or just cleaning it up in post using RX9 since I have that available too. Thoughts?

If it would help, I can cough up some recordings for reference.

Thanks in advance!