this is pretty interesting and could indicate things both ways. Either Russia feels they have the upper hand and want to put an emphasis on it, that they have these missiles they have threatened with in the past, and with NATO not coming, it is a nail in the coffin and Zelensky needs to stop... which is why Putin rejected peace talks this past weekend to level Mariupol and have some shows of force like this.
Or, with NATO and other countries not coming to save the day, but Russia is also feeling the pressure at home and feels a few more big haymakers can seal the deal. But that could also make them blow their load, as a number have suggested is the case, where Russia cannot maintain and needs it to end ASAP.
Based on what I have seen, I think the prior, and this is them testing the international community waters, seeing the general response, and after achieving some better land positions are now going to drop the hammer harder and get what they want.
And this isn't being pro russian, I just think that now that Mariupol is being leveled, along with lack of Western Support, the Russians now have pretty open Eastern Ukraine to advance through and take even more strategic positions and further encircle various urban centers.