Yeah, I guess whichever launcher makes the most sense really depends on which storefront you tend to use most.

I mostly use gog, itch and humble bundle, which lutris handles nicely. On the other hand, it isn't as streamlined as heroic for other stores, you need to install the egs launcher for lutris to run games from that platform, as an example.

Not exactly what you are looking for, but lutris does support itch.io. The way it is implemented, it won't list the bundle contents, but only games that have been added to your collection from the bundles, to avoid cluttering your interface / hide other games you purchased.

If not mistaken, it was included in one of those massive itch bundles a couple years back. If someone is on the fence, you might already have a copy of the game in your backlog ;)