Namless will punish you hard if you're overly greedy. You stuck it out till the end, props there. My playstyle involves a lot of perfect guards because nameless absolutely destroys weapon durability. It may be difficult, but that's my recommendation. While a dodge focused style can work, it may be easier to learn the timings and perfect guard a lot of nameless's attacks.
I’m only missing Free from the Puppet String ending to get my Platinum. I was struggling bad on this guy on ng+. So my question is, should I go into ng+2 to get the last ending, or should I simply make a new build and defeat him on regular ng?
I think starting ng+ would be a better choice. Maybe do some ergo farming before ng+2. In my first playthrough, I beat him on my first try, on ng+ took me about 2 hours to beat him, and on ng+2, I beat him second try (which is this video here). I think the first ng+ had the highest leap in difficulty, the next one wasn't so drasticaly increased. And giving the fact that you will get more levels, should make the second ng+ a bit easier.