Most professional post processing software does this and can be expensive. RTKLIB is only a single baseline processor. We have JAVAD Justin 3 and also TBC, however I hardly use TBC as we have all Javad gear here. I would recommend Javad’s software over any. It has a fairly steep learning curve and is about $2500 but it’s also considered as a scientific GNSS post processing software used in research. Honestly, it’s in the class of Bernese GNSS Software but is about a tenth of the cost.
There are others out there like CHCNAV and I have a copy of it also, but I haven’t really used it much.
Javad Justin 3 software really impresses me in the ability to filter out bad data. As with anything else, you get what you pay for.