Abysal boses to strong

Hi,
I’m playing a Titan Bear build focused on close-combat fights. I’m level 90, running a slam build, using Waystone XI (4 modifiers, nothing extreme) and doing Abyssal Tablets. I’m dying almost instantly when the Abyssal boss emerges from the ground — there’s no real chance for a fair fight. When I use Power Slam, I often die multiple times; the bosses seem to have too much life and resistances, making them impossible to fight in melee.

I’ve watched top players on YouTube using ranged ascendancies, and even they keep their distance and slowly deal damage. How am I supposed to handle these encounters as a close-range Titan Bear? At the moment, it feels like there’s no viable way to fight them.

Thanks.