DigiKam has come a long way, but it’s still missing some really basic DAM features. I’d love to stop using Lightroom and there are plenty of good raw converter replacements, but it’s the DAM features that there are no replacement for. In DigiKam an album is a directory on disk. A photo can’t be in two albums at once. They recommend using tags for more groupings, but that just seems clunky.
One of the things I really like about digikam is the matching of the disk layout with the album structure. This makes it really easy to have other programs also interact with my photo library in a way that's near impossible if you instead have an internal photo database.
Tags work great for me for multi-categorization. What feels clunky about them in your workflow? You're even allowed to have a tag hierarchy.
In my workflow tags == keywords which are orthogonal to albums. Keywords describe a photo and get published with the photo. One photo can be in multiple albums like Flickr Photosteam (published to Flickr), “Zion Vacation” (event album, published to Piwigo for friends and family consumption), “2022 Year in Photos” (yearly highlight album), “Favorite Landscapes”. Photos are in a date hierchary on disk.