One critical point I forgot to include is that cognitive load of your team members should be treated as a precious resource. Whatever happens, you need to make

One critical point I forgot to include is that cognitive load of your team members should be treated as a precious resource. Whatever happens, you need to make sure you don't waste this resource on unneeded stuff -- cognitive load more than anything else will determine how quickly stuff can be changed. Remember, if you introduce anything people will need to take time to learn, adjust and then understand. You can also count of experience at least temporary slowdown. So don't waste time things that only marginally help with development. You definitely don't want to switch your project from Java to Kotlin if your goal is to get something done quickly! (Yeah, I have seen this happen in real time -- new guy came to a project and "listened" to devs and switched project from Java to Kotlin with predictable outcome that he was fired half a year later after disappointing progress on actual work).