I've been testing Voukoder on Davinci Resolve Studio 17 and worked fine. Exports have good quality. The only problem that I found is that I am not able to export Prores 4444 with actual transparency. I've setup a clip in the Color Page to have alpha by removing the background and adding an Alpha Output in the node window. I have this settings in the Deliver Page and in Voukoder. I've tried tweaking them but the result is the same: what sould be Allpha channel just displays black pixels. I've tried to put it over another video to check the transparency, but it doesn't show it.
In order of screenshots
1: My setup of the Clip to have transparency in the Color page
2: My settings on the Deliver Page
3: My Codec selection in Voukoder
4: My Codec settings in Voukoder
5: Codec information of the exported clip in VLC (Davinci Resolve's inspector tab also displays Prores 4444)
6: Testing transparency (I've put the clip over another and scaled it down so it can clearly be seen the lack of actual transparency)