Speculation: Next
advance / artillery domination? 37 km, but I have no idea about the terrain or defences. I would hope Russian Federation has thinned out quantity/quality in this region as a desperate measure to help elsewhere.
I've heard rumours of Ukrainian reserves, newly trained/equipped in the west and some people wondering if they are available for another front.
The white lines are rail (I believe). In any case, if cut, then only roads left and Ukraine can threaten towards Melitopol or the coast - hitting/capturing warehouses, airfields and cutting off Russian Federation forces in Kherson, Crimea etc. These Russian Federation forces will grow weaker over time/winter and can be dealt with at leisure as they will have little to no ability to attack and probably have little winter survival equipment. Alternatively, Ukraine could capture large parts whenever their intelligence suggests success.
Ukraine has shorter internal lines for logistics to move men and material. Mobile northern/eastern units may transfer & join in, some of their infantry could remain and secure recent gains beyond Kupiansk & Lyman, but beyond having an eastern mobile reserve, there may be very large mobile forces there now, enough to spare in the south, especially after so many Russian vehicles have been captured. Ukraine can move the most serviceable vehicles south and improve a mobile reserve in the east from captured vehicles over time. Fixing them is training for new Ukrainian tank/recovery crews.
Northern/eastern Ukrainian forces presumably have good experience, leadership, morale but might need rest & refit. They could be used as a second wave if new troops are available to do the initial breakthrough. Infantry/artillery heavy breakthrough, mobile forces for rapid exploitation. It seems that so much Russian artillery ammo has been captured that the Soviet era guns can be used heavily, this vastly improves some aspects of Ukrainian artillery - volume, but not accuracy. Artillery and air domination should be morale-breaking for poorly led, trained and supplied Russian federation forces, especially if Russian officers have left and only ethnic-minority troops remain.
Whatever happens, I think the Kerch bridge attack will be part of a larger plan which will develop rapidly. You never know how long the target might be affected. You can count on hours, days. Weeks might be pushing it. Until you assess the damage and Russian Federation's repair abilities, you must be ready to decide and quickly execute on the next move. The Ukrainians probably have a number of plans for each scenario, including further attacks on repair efforts.
Stunning possibilities, but my speculation only and no secret as anyone else could consider multiple plans with great chances of success.