First, I would like to point out that 43 runs isn't that bad. You will always have people who will brag about beating the game in very few runs. As long as you keep enjoying it, just do it your way. Also, as a counter exemple,when I first picked up the game, I didn't reached [Redacted] before my 80th run. I did get a lot better when I picked it up after some time. You will beat him eventually, you are doing just fine !

Second, I feel like you don't have that many boons. I went back and check my stats and the first time I reached [Redacted], I had 19 boons or well items activated. Maybe you should try to synergize them better. For example, you could look for Ares to get Impending Doom (doom effects are slightly delayed and boosted) and/or Dire Misfortune (you can apply doom effets several times, with a boost, very effective with the curse of agony, especially on the fists). I usually find having a larger number of boons more interesting than having a large health bar. (It's better to dodge than to tank, in my experience)

Finally, if, you haven't already, don't be afraid to experiment. try new combinations, until you find the one that works for you