Been doing a lot of AA since yesterday. Up until AA my main focus has been merging my core, so I barely had any decently built units besides my 3 Askr units, my core, as well as a Minerva I use on my def team. So let's just say... It has been a struggle. I really want top 1k too, so I have to use my main arena team first match, and this means 702-714 matches with mostly scrap piles. First 5 hours or so for me was basically to find what units I had that could be useful, and I ended up using the 3* I have to atrengthen my good 4* units. I also came to appreciate specialized units, that can do one thing good: like Laslow with Axebreaker, I can bring him one time vs axes to save a better red for another match. I also got better at item usage: instead of trying to save items for later, I try and see opportunities to use items to save good units. For example, vs the common Bunny / SCorrin teams, I can give my Merric a res boost and use the Panic item, put him on a def tile and see him solo a game. After 10h I finally got a deathless run until final game with 3 good units left, so I took help from Roman here and some other guys on the FEH discord to round it up.
So AA was a struggle this week, but I'm already working on getting more options for next time. I will also make sure to save more 5* I pull from now on. Hoping for something tomorrow during Hero Fest! The good thing about the scoring system of AA is I can keep merging my core like always, which is nice, since +30 has been my goal for a few months now.