Agesilaus What class is your MC? Also, are you using a "good" party? My first run was as an arcane trickster with a nuanced morals and less conventional classes. It was an absolute slog. I replayed it with a Hospitaler Paladin MC and the mostly good party of Valerie, Linzi, Tristian, Ekundayo, and Jubilost. It was
far better. The game is all about attrition, and it's grueling for a full arcane caster. The experience is different enough to where I would even recommend re-rolling your MC to a martial if you've gone full caster. Slayers are also very well suited as MCs for this game, especially later when advanced rogue talents come in and you can just churn through the worst foes.
I've played Kingmaker a number of times with different characters, that's not really my issue. I'm just not drawn in to the game world and characters so much that I would willingly spend 100+ hours on a playthrough. However, I'm going to play through to the end of Act 5 at least.
I'm currently playing a chaotic good sorcerer with the green dragon blood line. I turned Valerie into a Dragon Disciple who can cast buffs, the barbarian lady also provides melee, the grumpy dwarf does heals, Linzi is there for bard buffs and spells, and the last person gets rotated a bit. Ekundayo is a little overpowered in my opinion, but hey whatever.
The combat isn't causing me to reload a lot or become frustrated, I generally approve of the tbs combat, items, spells, etc. However, if I just want combat I'll go play Battle Brothers.