In my experience, depending on multiple external ecosystems isn't all that much of a problem (as long as they don't get orphaned) in terms of development and ma

In my experience, depending on multiple external ecosystems isn't all that much of a problem (as long as they don't get orphaned) in terms of development and maintenance, but it can hinder internal code sharing and skill transfer. In particular, junior devs will take extra time getting up to speed on each internal app because it is in yet another unfamiliar language. But maybe you don't onboard junior devs all that often. Anyway, while different languages each have their own tradeoffs and benefits, doing a sanity check on whether the putative benefits actually apply to your use might be advisable. IOW, do you really care that language X has a faster startup time when the app written in it is a long-lived server process, so startup time isn't the bottleneck?