Advice on 5* leveling

metallion

Mods please let me leave this here first for better exposure.

So today is the day, the day that I draw my 13th Phoenix cover to put her at 5/3/5. It's even more incredible that she's maxed out considering none of my other 5*s are above 4 covers. So now I officially join the ranks of those who potentially have to sell a 5* cover. Totally not looking forward to that.

Anyway, should I start dumping ISO into her for more use? This is pretty much unexplored territory for me so I have a lot of questions. How will leveling her affect my MMR and scaling? I have just 9 champed 4*s, highest being HB at 282, so I'm afraid leveling her too much will mess up gameplay big time for me (I play for new releases top 100 and however far I can go in PVP). And even if I level her up, how does she fare in PVP? I only see OML 90% of the time, so I don't know what to expect from her PVP wise.

Thanks in advance.