It’s hard to lay it out for you with just words. So I’ll give a general idea of what works.
Step 1, huddle everyone into one corner of the map preferable behind something indestructible. With the nerds to spring breeze this is harder to do but not impossible.
Step 2, have your units all be able to attack the same square. if you have soleil in front put a trap two spaces in front of her then cover the side you aren’t leaning on. Place a ranged unit like Ophelia behind her. Then a dancer next to Ophelia with WoM, and maybe a horse unit on Ophelia’s other side.
Step 3, make use of the best structures. The tried and true structure here is renewal station. Upgrade that and put it further back while still brings an obstacle. Stack other buildings as obstacles as well. Armor and flying structure will get the most use. Upgrade your traps all the way they are the strongest thing in AR.
Step 4 character choice. Player phase works much better in this mode with maybe one or two enemy phase units at most. For builds I’ll say what stands out that you have.
Hector, give him vantage and armored boots and place a trap 2 spaces in front of him. Put an Ophelia behind him and your Olivia next to her and you have a scary team to attack into. With vantage if they don’t oneround or step on a trap you can vantage sweep.
Ophelia. Give her QP seal and set her up for turn 1 AoE and no one can safely tank her with few exceptions. Make sure she can’t be player phased and put her behind a 2 attack range unit like Soleil or Hector or Raven. Use her to trap.
Veronica, she can heal and buff. Use her to trap but be careful about her placement as she has a 4 attack range. Reinhardt is in the same boat and is also good but may be too easy to handle.
Mikoto with her staff is probably better than Veronica. Put her in the back and use her to heal and disable enemy follow ups. Give her miracle and support abilities. Her less range may make her better for trapping.
Soleil is hard to oneround for some but people may have too many counters to her. She may be good to run firesweep lunge on which can ruin a lot of people. She could work well. Just make sure you run lunge and firesweep. NYLaegjarn can do the same thing if you move her back a little.
WCecilia if you build her with bold could be potentially very strong offensively. It’s a bit costly though.
Another thing to do is put someone on the opposite corner of the map behind structures to turn stall. You can win this way fairly easily. Gwen and Sheena are great at this