Very old player, new to OSRS. Any recommendations for unique PK builds?

I have been lurking this sub for a while now, half interested in playing again but unable to make the commitment lol. I've finally decided to go for it, and I was hoping for some recommendations for what build to work towards. I started in RSC and had pure builds since then.

I've leveled up through a lot of different ones, mainly melee based. I usually enjoyed high attack high strength, but these days it seems attack levels are useless additions to combat. Also, I have most fun going for some unique build, even if its not the most efficient. For example back in the day I was one of the first to go to 30 defense on a 'pure'. This was before any benefit to it really, like the ability to have b gloves at 35 defense and the whole 95 prayer thing. I had 90+ attack and 95+ strength with 20 and then 30 defense, which in 2006 destroyed people because nobody had 'meta' builds. Today I'm hoping that there is actually some unique build thats half decent, even if its not meta.

I can see that its possible to have heavy ballista with low prayer and 33 defense. Is that at all worth the time and effort? Perhaps if I keep it approx 75 combat where most people won't have vengeance yet? I'm also trying to do some calculations to see if there are any stat combinations that make a chivalry build worthwhile. With the new obsidian armor I'm wondering if a 60 atk, 66 defense, 60 prayer build could have a higher max hit then 70 defense/70 prayer. Lastly, I'm simply considering a high attack high strength pure again. Maybe 90+ 90+ with 1 defense and 34 prayer. I understand zerks have an equal or even higher max hit plus vengeance, but I love using the whip to hit consistently, cause it seems nobody in the meta world levels attack past 75. I also see that you can get a crystal halberd with 33 defense at 100 combat. But even though that seems really cool to me...it simply doesnt stack up against an AGS.

Are there any possibilites than I'm missing? And are any of these viable in any way at all? I know its kind of stupid but I don

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