Proboards is an entire forum software, not a phone app. I see a LOT of info about converting from their software to Xenforo, so I am guessing is it is a mess.
And yes, tapatalk sucks. which is why Xenforo is the #1 software right now. Using Chrome/Firefox/Safari/Opera on a mobile device is so much more friendly, I rarely use it anymore. The only time I use it is on forums that still use Vbulletin, which has not updated in 8 years and
officially out of development. That software has not really seen a mobile friendly version. That is how dead it is.