I know your point of view is the accepted mainstream view, but I disagree and I never did it in 15 years.

Maintaining a gitlab instance, a mattermost instance, a kubernetes instance, an elk instance on a cheap VPS provider gets you in a pretty good place for very little money. Your internal tools won't need much attention until you hit a higher number of employees.

Also with three employees you can still get away with a lot of free stuff (eg. a discord or matrix server for chatting, private GitHub repos)