Abu Baniaz
TK Veteran
That is software limitation, not lnb limitation. With two satellite signal wires from a universal LNBs, you can have access to two transponders. You can record as many services as there are on the transponders. Not just two.What TV do you have? If it's anything like my LG C9 OLED then the Freesat tuner should have settings for both universal and unicable LNB's.
With a unicable LNB you'll get a similar experience to the Sky Q LNB you're replacing and should be able to record upto 4 programmes at the same time from a single tuner instead of just the current channel, as would likely be the case with a universal LNB.
Using Unicable LNB won't increase number of tuners.