Casual dad first time in endgame, how do I improve my build/ can I manage pinnacles as is?

The pinnacle fights are more about knowing the fights than they are walking in and deleting the boss. But even in that case, you should be fine with this character. You might catch an errant slam due to unfamiliarity but they actually aren't very difficult especially if you practice a few times on the lower difficulty.

If deaths aren't a huge concern for you with the xp loss, a good way to learn the fights is to just start up the t1 encounter, and don't attack the boss at all - just dodge their moves until you learn what they look like and how to dodge them. You get a few portals incase you die. By level 97 you should have a ton of frags for everything except maybe Arbiter.

Also simulacrum might be dicey lol but prob still fine.

youre looking pretty good so far! obviously the left ring can get some more damage but it obviously giving you a lot of resistances so that could be expensive. outside of that for pinnacles you could do with working despair into the build and then you can use a second weapon set with chaos skills wand and 2nd weapon set pathing to increase effect of curses

Your casual dad 1st timer approach has a better build than me at a higher level and I've been in every endgame running the same build haha. Your doing great and even before despair which is easy to get and some small upgrades you might want, your definitely pinnacle ready, at the very least the 1st level.

Not familiar with bow builds in PoE 2 yet but your gear looks pretty solid from what I can tell, my only question would be the bow, seems like it would be a hell of a lot better with a flat phys roll in the prefixes, the PDPS seems kind of low? If I'm wrong someone else can hopefully chime in.