In Freetube, reload is ctrl-R on Linux and Windows, and cmd-R on Mac. I have experienced the fact that if you leave a video paused for a long time (hours) then you need to refresh. If you have history active, after refreshing the video will resume from where you left, which by the way is better then actual YouTube where it will often resume from an earlier timestamp. I have not experienced the other issues you mentioned.
I agree, F5 would have been better since it is the standard on Linux and Windows. The only reason why I found out is because I’m used to do cmd+R on Mac (I use Mac at work so I got familiar with it).