This game is overrated trash, admit it

I tried to get into it again recently and it just sort of fell flat for me

I agree. And I only say this because I hate turkroaches

If you can't fight actual armies with 90 men you're doing something very wrong. That's more than enough to do anything you want. Are they all untrained peasants or something?

you can get unique units that can be leveled normally like the main character, so you can level their leadership a lot so you can have more troops

t. shitter

Their leadership lever doesn't influence the amount of troops you can have.
The key is to upgrade charisma and leadership in your character, you can easily get 100+ armies in little time.
And anyways if you have only 90, you can make those 90 very good units so you still can beat 150 or more units armies.

Why is the biggest problem recruiting troops after a loss and why isn't there a mod that fixes this? I don't care about total conversion mods, I just want the base game fixed. Oh there is a mod that fixes this? Nice, could you send it to me in the past, about 4 years ago?

Crybaby.
The game is supposed to be hard.

You might be able to get that "lance" system mod which changes how recruitment works and mostly solves that sort of problem. I've only seen it integrated into other total conversions, but I'm sure it must be available by itself.
Really the answer though is that an outright loss is supposed to be painful. Don't lose, pick your battles and retreat if you can't win. You pretty much always have options to avoid it, nobody forces you to fight unwinnable battles.

Yeah I don't have a problem with losing, but why should it take so long to regain the 100+ troops you lost that by the time you get back to the fight, the entire landscape of the war changes? I mean a king will declare war, a large army will engage you, the fight may not go so well, and by the time you are ready to fight again the war is over. This happens over and over and over. Seems really silly, especially if you have a ton of money. Maybe I should try modding it in myself.

The consequence of losing your entire army is that you can't participate for a while (unless you have another army stashed stashed somewhere).
After a certain point in Mount and Blade money becomes meaningless (usually when you own your first town), so if you could instantly get your army back there would barely be any downside to losing at all. You could throw your army at that enemy king, lose, do it again, lose again, and then come back once more and finish him on the 3rd attempt. It would remove any possibility of enemies doing lasting damage to you.

You could mod cities to have higher level troops that can be acquired for a bigger price.
Generally what you describe is not a problem once you have a castle.

You now you can take down lord armies all by yourself with horse archery and some skill and a luggage full of arrows.

Have your guys hold position and go thin the enemy out and deal with any dangerous units, the turn the enemies away and charge your units at them from the rear.

You can put you guys in a safe spot in a siege too and shoot down enemy ranged. You can even retreat and do this many times until the garrison is empty and take the town that way.

protip: once YOUR de jure villages become supportive of you, they'll give you more and better troops when you come to recruit volunteers (the higher the acceptance, the higher the default unit tier)