Roman here. We have a joke that we cannot dig a hole in the ground without finding a piece of our past, and that makes us hard to progress. Now we are also finding pieces of someone else's past. We are doomed.
Indeed, with a big BUT: you don't want to overvalue loyalty in respect of competence. You don't want to have a boss that is not good but "is here since forever".
Instead, reward them economically. Everytime the company takes a leap forward, make clear to them that they were important for the process, and share some profit.
And make clear that being important in a moment doesn't automatically mean they will be important in the future: they will have to compete on results, like everyone else.
Maybe "best ever" is too bold, but both proven efficacy and mainstream popularity for over 15 years, without being a bulky thing everybody just accept (like vscode), I don't see many other software examples.
Anyway, sorry for triggering you with the first bold statement! I actually wanted to emphasize the curiosity over jj.
I consider git the best software ever written. I used to work with some other SVCs, and I cannot thinking on leaving git now. Somehow, I feel it like a limitation for my mind.
I'm following this Jujutsu project, I'm genuinely curious to see what it can bring to the SVC scene.