If you don’t do side quests, the main quests have enemies several levels higher than yours and they kill you with a few hits. You simply can’t fight enemies outside a certain level range.I don't know why anyone would need to grind, boost levels or buy XP multipliers especially for Origins, to me it was the easiest of the last 3 AssCreeds. I for sure liked Origins with Bayek and Aya much better than Valhalla and Eivor. I loved Odessey the most playing as Kassandra. She was a fantastic character. The voice actor for Deimos sucked apparently.
I really liked all 3 of the AC RPG-like games and I'm not sure why people love to hate on the series so much. I've never spent a cent on MTX and I don't even notice them in the games. I have bought the season passes for Origins and Odessey and they were well worth the money. They had tons of content, great stories and wee much better than so many full games. Fate of Atlantis was awesome.