Antenna dBi for indoor deployment

I’m looking to install a number of sensors in an indoor environment on multiple floors (up to 10 floor buildings). I was under the impression that lower dBi antennas provide better overall coverage at the cost of signal strength, whereas higher dBi antennas concentrate the coverage area more, but increase the signal strength.

However browsing the Antenna Kit on the Rak store, they provide antenna options up to 8dBi for an ‘indoor’ solution. This is counter to what I’ve heard where indoor deployments benefit from lower dBi antennas as they provide better coverage.

Does anyone have any experience with multi story indoor deployments? Would I benefit from upgrading the basic antenna that comes with the RAK7268 to a 5 or even 8dBi antenna? Would it be possible to get away with a single gateway for a multistory building, if I put a larger antenna on it?