I primarily found that when importing photos, it would take Photoprism a long time to generate thumbnails. It was long enough that I would give up on trying to sort through the photos after uploading and come back a few hours later

Alternatively with Immich, I dumped ~100 Halloween photos taken with my phone and DSLR onto the server. They were already previewable by the time the files were done uploading

I've already uninstalled Photoprism so I couldn't tell you what my config was. Could have required more tuning; but I'm at a point in life where I'm leaning towards needing things to "just work", than to have to tune things

Re: Unclean: IIRC, Photoprism gives you a lot of tools and options. More options and features = more stuff on your screen = a more cluttered UI. While I did like the tools, it also made it difficult to share with normies