i know exactly what you are going thru :bang head: first id rebuild the slave cylinder, cheap easy to do, this will save you from bleeding the system twice. but then ya new fluid, bleed system and go from there. if that still doesnt help(did only for a bit on mine) i ended up chg my master with a new one and problem is 97% gone, once in a blue moon it comes back but very rare now. There are lots of options for masters if you dont want a factory one.
i found that when you cant get it our of gear to N id have to not creep with the bike, like if you were in traffic, had to fully let go the lever while moving even if it was slow, then when you re-grab the lever pop into neutral. other good method is when slowing down from second, just tap lightly into N and not 1st.