I just made sure to put soldiers on the stat that was most suited for them. With covert missions you can get +stat boosts.
Usually Grenadiers have Aim issues, so you try to give them some through weapon upgrades/pcs. Assault that end up with Killzone and Shred. Specialists that have both hacking and healing with Rapid Fire and Run and Gun. A sniper that has both Rapid Fire AND Chain Shot on top of their regular skills. The Xcom skills get randomly generated, but you can still create super OP soldiers that way. There are random missues and covert missions that grant you the option to get plenty. You never have to worry about scientists/engineers. Once you get some soldiers up and running you’ll just tear everything to shreds. Sure the lost can feel overwhelming, but you can kill 20 a round, even early game. Other then that the game provides many mitigation/control options for the player that it does indeed remove a lot of challenge. Also management of tired soldiers can be an issue for some.
It takes some practice to understand her movement so you won’t take damage. Early game you only have to worry about the Assasin. WoTC does have odd difficulty curve scaling.