Not really "DYI Building" because I didn't build anything. But maybe this is still interesting for you...
Japanese DYI-Synthesizer-Builder "HAGIWO" built a Eurorack-effect module based on a DSP module which he purchased on Aliexpress. You can find his Blog here (use the Chrome functionality to translate the page from Japanese). I didn't find the exact same model that HAGIWO used. But I found this one: www.aliexpress.com/item/1005001859906930.html
When I saw the picture of the back of the PCB, I thought that it is probably easy to connect the module to the AE Modular. It runs on 5V and has one input and two output connectors. And it turned out that I was right: it was very easy to use this module with my AE Modular system.
I made a short video:
The module has 100 fixed effects. There is no way to change parameters of the effects like reverb time or delay time etc. But it sounds really good. Now I have to build a case so that the module is not lying around on my desk