The Christmas event coming up in a month or so will solve your QP problems. There will be a thread here nearer release with example teams for farming that event.
As far as upgrading your Space Ishtar goes, just make sure you’ve fully cleared Saber Wars 2, including the event shop. It has the majority of her upgrade materials.
You have command seals - use command seal revives if you have to so you can beat the two challenge quests after the event story. I’d even argue that for the last fight “Dark Rounds Shadow” it’s worth a SQ revive if necessary as Lores are an upgrade material that slowly trickles in (we get 2-4 per event, you use these to upgrade skills from lv9 to lv10).
Seeing as you asked for help - here’s my event support list & friend ID:
Make sure to tell me if you send a request so I know who to look for.
If you get Skadi, make sure you trade your exchange tickets (the daily login reward) for Eternal Ice and Aurora Steel.
Those tickets are handed out as monthly versions (so any tickets received this month are labelled “October”) and each month’s tickets can be traded for different upgrade materials. This month and December’s tickets can be traded for the materials I mentioned.
Merlin Sanzang with BG/NP levels was “best” in terms of total clicks to kill Barb. Tbh double Merlin wasn’t ideal - you wanted Lancer Raikou as she gave debuff clear and nearly Merlin level steroids.
That event was probably what alerted me to Laikou’s value. Now I have her (& NP1 Sanzang/Merlin) there’s no Barb rerun in sight
I like that raids aren’t too restrictive, we had a bunch of people Bond farming the Oniland raid with different Servant choices. I took it as a chance to bump Kama some more; I’ll bring her out whenever she’s a relevant option.