you’re right that urien struggles against pokes. blocked shoto sweeps leave them at -13, but urien doesn’t have a fast super to do raw or tag onto the end of his own poke. the best you can do is c.mk to punish a blocked sweep. ex tackle is also possible, but urien players tend to prefer saving meter for aegis setups and bigger damage in combos. it’s not guaranteed (it can be teched, srked, backdashed, jumped out, etc.) but you may also choose to dash into throw after blocking an unsafe sweep once in a while.
this is one reason why the footsie game is so important for urien. blocking pokes generally doesn’t get urien anywhere, but on whiff, you can punish with c.mk, s.mk, or s.hp (a little harder since it’s slower). so make sure you learn how to walk in and out of ranges to force whiffs to your advantage. in certain cases, you can also punish whiffed standing pokes with ex headbutt into a full combo. if they did a low poke, usually you’ll fly over them and be able to throw before they recover. learning to integrate your pokes into a stable ground game is more reliable than the habit if trying to ex headbutt everything, though.
if i had to break down urien’s ground game options in a basic way, it could go like this:
s.mp: builds meter, stops dashes, useful against some high pokes (chun’s)
s.hp: can be used against low parries or whiffed low pokes
s.mk: stops dashes, useful against whiffed high pokes like ken’s s.hk; generally used at or near max range only
c.mk: go-to low poke for footsie use and punishing sweeps (when possible)
j.hk: used against the opponent’s ground game. if you jump with careful spacing and see the opponent whiff a move while in the air, hit with j.hk. if you see a slow crouching move like a sweep, hit with the j.hk deeper to combo off of it. if you see that they also jumped, you can press it early for air-to-air. so yes, urien does have to jump to access one of his best/most versatile normals
c.hk: too slow to punish whiffs but highly useful when advancing on certain characters like chun
jab headbutt: beats throws (generally), goes over low moves at close to mid range, stops dashes and early jumps
ex headbutt: same as above but goes over lows at max range as well, leads to full combo
combine the above with the ground game sticky on the main 3s page to get a good understanding of how to approach it with urien. something to keep in mind is that you can’t realistically win with urien using only basic ground game technique. this post doesnt concern aegis, combos, parries, etc. because it wasnt relevant, but you’ll need a good grasp of all of those for urien to be legitimately threatening. the ground game is meant to supplement cornering the opponent, low fierce, anti-air sphere, ex headbutt, and the other scary things. if you would rather focus on ground game only, i would recommend not using urien.