I don't know why do you consider RPi for DVB-S2 server. KI Pro with internal DVB tuner is much better solution. Internal tuner has HW demuxing and it causes very low load for CPU. You can extend number of tuners by external USB tuners.
Can I run LibreELEC on K I Pro?
I was thinking of getting one since it seems cheaper than buying a DVB-S2 USB stick.