Ukraine wants permission from the west to use long-range Storm Shadow missiles to destroy targets deep inside Russia, believing this could force Moscow into negotiating an end to the fighting.
Senior figures in Kyiv have suggested that using the Anglo-French weapons in a “demonstration attack” will show the Kremlin that military sites near the capital itself could be vulnerable to direct strikes.
The thinking, according to a senior government official, is that Russia will consider negotiating only if it believes Ukraine had the ability “to threaten Moscow and St Petersburg”. This is a high-risk strategy, however, and does not so far have the support of the US.
Ukraine has been lobbying for months to be allowed to use Storm Shadow against targets inside Russia, but with little success. Nevertheless, as its army struggles on the eastern front, there is a growing belief that its best hope lies in counter-attack.
They’re not “just holding back”. They’re just not going all out because of similar “domestic political concerns” as the western countries. It would also come at a much greater cost to foreign politics as you risk upsetting allies who now have to sell that to their own people to justify providing support.
Keeping a steady defense of a buffer zone between them and NATO is a much easier sell than a full military invasion attempt especially if, as you suspect, their full potential isn’t as great as some think. Hence why it started as a “special military operation”
I don’t dismiss that potentially part of the reason they arent going full speed is that their power isn’t as good as they portray and many believe, and they don’t want to expose that weakness.
You asked why Europe would want to avoid pushing Russia too far.
You can either come up with a complicated answer involving Russia having a vast reserve of undemonstrated military might and thinking that anyone found the “denazification” excuse plausible, or you can remember that they have nukes and even with a military that poses no plausible threat or defense to NATO being a nuclear power is a great deterrent.
Why, lacking evidence to the contrary, you would pick the more complicated explanation is a mystery.