Some of the battle master maneuvers say they only work on large or smaller creatures such as the language for trip attack:

Trip Attack

When you hit a creature with a weapon attack, you can expend one superiority die to attempt to knock the target down. You add the superiority die to the attack’s damage roll, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, you knock the target prone.

Same is true for push attack. The language for the limit with grappling though isn't as restrictive, its one size category larger than you:

The target of your grapple must be no more than one size larger than you and must be within your reach.

I ask because I have a bare knuckle brawler build I want to use for a one shot but it sounds like there are giants. To my reading it looks like RAW being enlarged would let me grapple a giant but not use some battlemaster maneuvers I'd like to use. RAW a halfling battle master could push an ogre 15 feet but an enlarged goliath couldn't push a giant. But that same halfling couldn't grapple the ogre but the enlarged goliath could grapple a giant. Seems a little wonky to me.

Is there some way around this or would that have to be a DM homebrew ruling?

It would basically have to be a DM homebrew thing. I think the reason they chose to have the more restrictive language for Battlemaster explicitly for small creatures so that they don't lose the ability to use these unique techniques against anything but medium-sized opponents. I don't think it would be hard to get a DM to agree to let you target even larger creatures if you yourself are also enlarged... one of the nice things about D&D is that it encourages DMs to adjudicate these complicated issues that feel like they should logically work but don't necessarily fit RAW.

The language of the BM Fighter abilities that are based on size assume the PC is Medium sized.  It really should read "up to one size larger than your character" since that is likely the intent.  It would be a stingy DM who refused a player the ability to use a core subclass feature when you or your party take the trouble to use the Enlarge spell and whatnot.

To reinforce what was already said, the devs often didn't think thru non-standard cases & locked in everything as if players would always be the default state, such as Medium or Small size, 5' of reach, 2 arms, and so on.  The Enlarge spell (or Rune Knights), polearms, & thri-kreen, and many other things clearly were ignored when the rules were written.  Because obviously it is ridiculous that a Giant Battle Master couldn't trip another Giant, but a Tiny Fairy Battle Master can trip a Ogre.

The RAW way around it is to shrink all your Huge+ opponents.  The RAI way around it is to grow to be at least 1 size less than your current opponent.

Sadly, I've known some rules lawyer DMs that very likely would not allow an Enlarged BM Fighter to use Trip Attack specifically because of RAW.

Quote from Song_of_Blues >>

Sadly, I've known some rules lawyer DMs that very likely would not allow an Enlarged BM Fighter to use Trip Attack specifically because of RAW.

 
I am a Rules Lawyer and even I would allow it. 🤷‍♂️

Quote from _Amunsol_ >>

Some of the battle master maneuvers say they only work on large or smaller creatures such as the language for trip attack:

Trip Attack

When you hit a creature with a weapon attack, you can expend one superiority die to attempt to knock the target down. You add the superiority die to the attack’s damage roll, and if the target is Large or smaller, it must make a Strength saving throw. On a failed save, you knock the target prone.

Same is true for push attack. The language for the limit with grappling though isn't as restrictive, its one size category larger than you:

The target of your grapple must be no more than one size larger than you and must be within your reach.

I ask because I have a bare knuckle brawler build I want to use for a one shot but it sounds like there are giants. To my reading it looks like RAW being enlarged would let me grapple a giant but not use some battlemaster maneuvers I'd like to use. RAW a halfling battle master could push an ogre 15 feet but an enlarged goliath couldn't push a giant. But that same halfling couldn't grapple the ogre but the enlarged goliath could grapple a giant. Seems a little wonky to me.

Is there some way around this or would that have to be a DM homebrew ruling?

 
The difference is that a Small PC cannot Grapple or Shove a Large creature, but they can Trip/Push Attack ‘em.

I don't think it's fair to say the devs didn't think it through. There are competing forces here - you want it to feel realistic, but you're also trying not to make small characters absolutely garbage at whole swaths of class/role options. As has happened in many (but not all!) cases where balance has clashed with verisimilitude, WotC erred on the side of balance and inclusion.

A more legitimate complaint I think is the inconsistency between an absolute size reference in maneuver wording versus a relative size restriction for grapple/shove. Personally, I'd be fine applying the latter logic to maneuvers and just about anything else that dealt with similar strength-based contests.