How it works with a team More than one person? How many merge conflicts it gonna introduce with just a team of 4? Mono repo also means that merging both front

How it works with a team More than one person? How many merge conflicts it gonna introduce with just a team of 4? Mono repo also means that merging both frontend and backend into one, even with totally different languages? Should be fine with traditional web framework but how it will become for API+ SPAs?