Sounds like you doesn't use latest version of Fedilab Lite, because Pixelfed is supported since version 2.23.0
Fully fledged Fedilab supports: Mastodon | Peertube | Pixelfed | Pleroma | GNU Social | Friendica
I'm using the free version from f-droid.
@Wolfram I'm using fdroid too and my versions are older than yours, e.g. 2.22.2 for Fedilab. And yes, I just refreshed. 🤔