Bakhmut Update
There seems to be a consensus that the Ukrainian brigades trapped in Bakhmut cannot get out. An effort by Ukrainian forces to relieve the forces in Bakhmut appears to have stalled. (There are three Ukrainian brigades not too far away, but they are needed to form a new defense line after Bakhmut is over). Any formation approaching Bakhmut would have to run the gauntlet of Russian artillery and air strikes.
According to reports, there are four or five Ukrainian brigades inside Bakhmut, which are being systematically pounded. This could constitute between 20,000 to 30,000 men (at full strength).
Among the units reportedly inside Bakhmut are
1. the 93rd Mechanized Brigade
2. the 3rd Operational Brigade called Spartan
3. the 3rd Assault Brigade called Azov ( the 1st Presidential Brigade of the Ukrainian National Guard)
4. the 58th Motorized Brigade
5. and a "volunteer" (conscript) brigade or units around the size of a brigade (Green armband troops, poorly trained)
There is talk that Ukraine may launch an offensive elsewhere, perhaps in the Zaporizhia area, to try and draw off Russian troops. But Russia has large troop concentrations on nearby Russian territory, so such an attack could prove disastrous for Ukraine unless backed up by outside help (e.g., US or NATO forces).
No one really knows the level of casualties in Bakhmut. Given the precarious position of the Ukrainian defenders and exposure to Russian artillery and air strikes, it would appear that the Ukrainians are taking the heaviest losses.
Wagner forces now completely control eastern Bakhmut including the Bakhmut river. They may already be moving into the center of the city, with progress reported street by street. The Russians have also taken part of the northern suburbs of the city and are continuing to slowly advance.
Zelensky runs the risk of losing a highly experienced part of his army to the Russians. He also faces dissatisfaction in the military, especially if part of the Azov troops are killed off in Bakhmut.
It remains to be seen if there is a surrender or "another Mariupol." You will recall that some Azov fighters held the steel mill (Azovstal) which was laced with bunkers until they were eventually forced to surrender. There is an industrial site in Bakhmut that potentially could serve a similar purpose, but you can't shove 20,000 troops into a place like that (compared to the few hundred in Mariupol), so I don't think a "last stand" operation will happen. Russia has also introduced its own JDAM-like bomb called the UPAB-1500B. This is a Glonass (GPS) glide bomb that can be launched by Russian aircraft (Su-24m, Su-34, Su-35, MIG-35) and carries a 1,000 Kg warhead (including a bunker-buster version). The UPAB was not available to Russian forces at Mariupol, but it is now.
Allegedly the Ukrainian forces have been ordered to fight to the last man. How long that order will stand remains to be seen. Bakhmut could drag on for a few weeks while the defending forces are liquidated, or if they are relieved (which is unlikely). The other alternative is a surrender.