PoP is a bit too grindy for me, and when you get farming qualis gems you end up godlike
The problem with total conversions is there is often some severe imbalance. For instance, in Warsword Conquest you can kill trolls solo in the early game which are melee only bandits that give 1,000xp and about 3000 gold per party, and in Gekokujo samurai blow ashigaru out of the water and with a limited party size it makes sense to use pure samurai cavalry for field battles and samurai archers/gunners for sieges, but the AI will tend to use a mixed party and you can wipe out 1,000 guys with an army of 150 no problem.
Native doesnt have a single bandit type that doesnt have some form of range weapon, except looters which are a rare spawn or specific infantry deserters, which makes soloing the early game hard, and encourages the use of a manhunter army for reliable cash grind which can take some time to build up. While pure army types are very strong, especially cavalry for field battles, garrisons tend to be nothing but top tier units unless they were sieged recently and even pure infantry or crossbow armies struggle to strip them down sometimes, the OP party skills allow for repreated assaults at little cost though. WFAS also has lots of gun bandits and a lack of manhunters (unless you customize mercs) means trade becomes the solution, and in Viking Conquest again most bandits have a range weapon, and this time infantry are the only viable unit meaning you can't just use mass cavalry or mass archers in a strong position and cheese the AI. In WFAS they nerfed engineering, and in VC engineering was still nerfed, and also training times were severely nerfed forcing players to pick and choose battles, not risk their elite units on a whim, and with the high penalties for injury and battle fatigue it makes soloing the world much harder and shifts the focus away from solo battles and towards politics in order to field a powerful force and rely more on the soldiers of allies which made for a far more challenging campaign
Most mods will have some form of easy bandit that gives high exp, money and renown that 'solves' the early game, some kind of unit that, coupled with the mixed AI army types allows you to easily solo armies 5x larger than yours, and the severe imbalance in engineering, surgery, pathfinding, training and wound treatment that allows you to just zoom around the map zerging fiefs and healing your troops and training replacements literally overnight. The late game becomes a slog of rushing from one fief to another and storming it instantly, perhaps over 3-4 assaults to whittle the garrison down with occasional trips back to the castles for reinforcements. There's a deep economy and political system that become totally unnecessary as you just give all your captured territories to a few lords to manage while you do everything yourself
I just had a very satisfying native game with realistic saves where I put the practical knowledge of economy and politics I had gained to build an empire with over 40 happy vassals, and by the time I moved to conquer the Rhodok and Sarranid kingdoms they had over half their territory yet not a single vassal due to my political sabotage. I might just autoresolve all my battles in future and try to think more strategically about kingdom management and politics because its far too easy to exploit battle AI and imbalancing to conquer the world