I know people hate on Electron (sometimes rightfully so), but this does seem like a nice use case, meet your users wherever they are, even offline!
As for when I need something native, Kdenlive is pretty nice: https://kdenlive.org/ (it's FOSS, they could probably also use a donation https://kdenlive.org/en/fund/)
Oh and DaVinci Resolve, even though effects aren't the main focus (it's a fully featured editing suite): https://www.blackmagicdesign.com/products/davinciresolve
I know people hate on Electron (sometimes rightfully so), but this does seem like a nice use case, meet your users wherever they are, even offline!
As for when I need something native, Kdenlive is pretty nice: https://kdenlive.org/ (it's FOSS, they could probably also use a donation https://kdenlive.org/en/fund/)
Oh and DaVinci Resolve, even though effects aren't the main focus (it's a fully featured editing suite): https://www.blackmagicdesign.com/products/davinciresolve