I've seen posts where people say they are level, like ...150 n stuff. I played a character once to level 48 and couldnt get much higher than that with my major skills being almost maxed, how does one go further than that?

In the vanilla leveling system, like seems to be your case, becomes much harder to level beyond 50, and this is someway a designed feature. Mods can change the leveling system. Among several others, Kobus Character Advanced System (search for Kobu) is the one I use, since it allows a large range of possibilities. Another way is by removing the skills cap, like the Legendary Mastery. And several other ways including console commands.

Just remember most monsters and NPCs levels are dependent on the player's level. Just enhancing the level without adequate support from skills, attributes and mainly "gears" may turn the game very very hard.

Edit: Alternative to the Legendary mastery is Elys Uncapper . Never used this one, but I was surprised by a message on the former saying it deprecated and pointing to Elys uncapper.

and this stuff works smoothly with an overhaul mod like CUO and OOO?

basically that's what I wanted, a couple names to search for, learn a bit, awesome, thankyou

Yes, they do

thank you kindly