[Unusable after download]

I downloaded Affinity Photo 1.10 from the online store this weekend.

I tried doing some simple photo editing using the brush tool to create some layer masks. It would periodically crash when just using the brush tool. After a number of crashes the program would freeze on opening, looking like this:

Rerunning the installer and selecting "Repair" didn't fix anything. Eventually I restarted my computer and it started running again, but now it is incredibly unresponsive. If I click around on tabs or try moving them in the right sidebar it will frequently freeze up. The top bar will say "(Not Responding)". 

There are no crash reports.