I don't think the Kagi team has any bad intentions, and most likely they have attended the anti-Vucic protests as well. Moving back to Serbia is an economically wise choice for Kagi as a company.
However, once regime goons show up in Kagi's offices, they will be forced to do whatever the serbian government and by extension putin wants them to do.
Often Kagi gets mentioned alongside Protonmail and related privacy-focused services. But Switzerland is a totally different country than serbia to operate it.
It's a risk we should be aware of and consciously decide to accept when we are using Kagi.