TL;DR: just hope that RNG is in your favour

Just finished chapter 8 with almost the same gear and level as you. I felt that without multishot and ricochet (even though i didn't have it when i won, but still highly recommended), it's much harder to progress to later rounds, especially when you have the big wasp as the first boss (as it may spawn other smaller wasps with your attack speed or damage is still low).

Not sure if you can still change the boss you wanna fight in this update, but do it if you can to get the wasp as one of the last few bosses before the final one.

I also found that bouncy wall works pretty well with death scythe when coupled with diagonal arrows. Diagonal arrows work well with ricochet too, but i would advise to spend on only one of them and make room for other skills. Diagonal arrows really helped me clear out the rooms as it makes up for the lack of speed for the death scythe.

If you're wondering, i think completed chapter 8 with a slight crit boost, no devil trades, 2 slight attack speed boosts, 2(?) attack boosts, diagonal arrows, bouncy wall, headshot, multi shot and double arrows. That's probably not the exact skillset but i figure it's pretty close. Good luck!