when the invasion is over, most wouldn't want the Ukrainians to have no way to defend themselves from another attack from Russia,
a far-right battalion ( AZOV ) have been well armed since 2014 whilst fighting the Russian backed ( and even better armed ) separatists, so nothing will change in that aspect
The world had to do something and sanctions were one of the easier options, personally, I would prefer for the UK to try and put pressure on Russia with sanctions than do nothing, unless you think that asking Putin politely would have been enough to get him to turn around the tanks