Obviously this wouldn't be Market Garden 3.0 (since we all know how 2.0 went) but an amphibious stealth landing disguised as a full assault designed to draw men away from Zaporozhia, an armored punch from Zaporozhia using NATO equipment with the goal of driving as hard as possible to threaten an encirclement of the Russian forces dug in on their side of the Dnieper... I'm probably misreading the map badly but they'd have good odds and there's a fair bit of partisan activity behind the Russian lines there, too.
The problem with this scenario is that Ukraine lacks the ability to land armor - they don't have the equipment. Any landing without armor is doomed, even as a diversion. Now could they do some 9-D chess move with decoys? Sure, that's possible. But this would only make sense if you want to pull Russian troops away while you strike at like Donetsk, but if you are wanting to try to cut off Crimea it doesn't - it would just get Russian troops moving and active in the areas you want to hit.
Putting Marines down to dab on the Russians and then go back home is still useful. It keeps the Russians off balance and you are keeping their scouts reporting constantly about activity - so if you did do anything, the first reports will be just more routine UKA activity. It also will keep Russian Command edgy and keep soldiers there instead of anywhere else on the front.
Ukraine has clearly husbanded its strike aircraft and drones. They have also not used their JDAMs yet. It's possible to do this if they let loose a barrage along the entire front to mask intentions, but focus the really heavy hitters for the kherson direction. Pound the crap out of the artillery and C&C in that area while the bridges are getting overnighted and then start moving quick. The bridges don't need to last forever. Just long enough to get troops across. Start with the Bradleys and strykers racing ahead to secure a buffer area and then bring up the tanks and light infantry.
And it needs to last longer than getting troops across. Unless your thrust is going all the way along the Dnieper to Orikhiv, you are going to need those bridges to stay up while you dig in. Russia is low but not out of long range missiles - yes, we've seen they are shit, but less so when able to get precise coordinates for what they're trying to hit and its static (see: story of that Foreign Legion brit of them getting rain of fired after like three days in country). They absolutely would blow their reserves to try to cut off a cross river action.
We were making fun of Russia making moves to try to hodl Kherson with only a pontoon bridge - that was routinely getting BTFO - for supply. Ukraine would very likely find itself in the same situation.
Even if we want to pretend that Russia's SAM operators & fighter pilots all decide to go on strike on D-Day, and a deep-cover Ukrainian operator penetrates into the Vatnik Shaker Central telegram channel and gets every artillery commander to post their GPS coordinates to "pwn the NATOrds" and Ukraine is able to just level every single artillery position in the Oblast, we've seen how the fronts settle into WWI static emplacements. Ukrain would need to keep that front supplied for a long time, and temp bridges won't do it.
I'd assumed all that shit was for later use, just in case of a Ukrainian crossing/breakthrough; but now it looks like they'd always planned on falling back to those new trench complexes, regardless of any Ukrainian offensive in the area. They may intend on letting Ukraine advance & become over-extended, then try to smash them in the open in prepared killzones & minefields.
That's my assumption about why Russia has effectively surrendered the immediate left bank to the Yooks. With a physical barrier like the river there is no need to dig in on the mudflats. As long as they maintaining effective overwatch, they'd have forewarning of any sizable Ukrainian action, so might as well let cross get over extended, then hammer the bridges and troops in open mud fields.