RAW, Conditions affect creatures, not objects. Thus, as per RAW, there is no such thing as a “Paralyzed Object”.
And DMG page 246 states Armor Class and Hit Points for objects. Note that these rules make zero distinction between immobile and moving objects, which in the mind of most players don’t make any sense at all.
However, it always remains the DM’s decision to apply RAW “as is”… or not!
My personal experience is that using this RAW rule “as is” leads to extremely high levels of frustration for the players. What should be a dramatic scene, inevitably turns into arguing about things not making any sense and that is plainly NOT fun. PCs will try to strike objects in combat (else there is no need for such rules at all) only when it is absolutely vital to do so, say to try to destroy an important evil magical McGuffin item before it is too late. But not even being able to hit the broad side of as barn feels very “ANTI EPIC” to the players. It can ruin an entire game.
So I recommend ignoring the RAW rule and going like this:
Vs immobile objects: Advantage! And if spending Inspiration: Auto-hit!
Fragile Items: Lower their AC by 2.
And for items that DM doesn’t want destroyed way too easily: use a “trick”:
a) Item has magic on that increases its HP or is “special” extra resilient. Damage shows cracks (aka player progression) in the force field or item.
b) Instead of needing to break a single item, PCs need to break several.
Maybe a mix of both: Say the PCs need to destroy magic pillars that make the boss monster “invulnerable”. Say, a big central pillar surrounded by 6 smalller pillars. The PC with lots of smaller attacks can take care of the smaller pillars, while the PC heavy hitter caN taker care of the big central pillar. The general idea is that the DM decides what ambiance feeling he wants to achieve with that “special scene”.
- RAW rule: zero progression on destroying the item until one of the PCs finally lands “the” lucky hit that ends the threat.
- Modified by DM: A feeling of progression towards a goal to vanquish a threat.
I know which one a DM with good judgment should choose.
RAW rules are often superbly useful, but they are not to be used as “horse-blinders” either.