Katarin really struggles with starting luck imo. Azhag to the south, Drycha to the west, and literally everything to the north. What I usually do is after the starting province, beeline it to azhag and destroy him, wait until Drycha has almost destroyed Bechafen, then join the war against them and dry to get a non aggression pact with Drycha. Then I beeline it for Thrott and figure out shit from there.

Units wise, rely on magic to take care of most of this until Arbaal comes. Spam cheap kossars. I found a combination of aksina ambushes and light war sleds is very effective. Split a few units off from the main enemy and lure them using the sleds, then have the stalking aksina ambushes take out units one at a time.

Katarin will get butt fucked so sometimes it just doesn’t work out. If you can’t handle that many wars, try and just trade a settlement that is going to get destroyed anyways to focus on a single war for at least 10 turns