The two swords bought by the apostles were not only to fulfill prophecy, but as a result of this display or brandishing of swords, then also for self-defense against others armed, in the coming days, during the remaining times that Jesus had on earth and afterwards, by them, the apostles, as they would spread the gospel into foreign lands. I would not be surprised that the apostles took Jesus' words as a clear signal to invest in self-protection during their travels against wild animals and unsavory persons along their treks.
Yes, Jesus' instruction to buy swords was primarily to fulfill prophecy, as he explicitly states, "It is written: 'And he was numbered with the transgressors'; and I tell you that this must be fulfilled in me".
This implies that the swords were a means to ensure Jesus would be seen as a transgressor, aligning with the prophecy in Isaiah 53, where the Messiah is described as being "numbered with the transgressors".
Then this would also certainly then make the apostles potential future targets of opportunity by anyone that hated Jesus and his followers. And it's obvious, that their lives, per implication and in scripture also had to be protected.
The swords were then intended for self-defense, as Jesus mentions, "But now if you have a purse, take it, and also a bag; and if you don’t have a sword, sell your cloak and buy one". Again, suggesting that the disciples were to be prepared for potential threats. Despite this, Jesus later rebukes Peter for using a sword, saying, "No more of this!" , for that purpose ONLY, which indicates that the swords were not meant for continued actual violence or self-defense at that particular time towards other or all the Roman soldiers.
I believe this is the rational today behind personal, family and home self-protection. This is as far as I'm willing to go myself. And not to popularize and prescribe to and cheerlead national leaders, men and now women to become pawns in a chess game of the rich, influential and evil ones in this world, dispensed out as cannon fodder, the age old process of the killing fields, used well before Christ.
To me, this is well beyond the limits of living a true Christian life and also wanting (national) revenge or deadly aggression against someone who is not my enemy or are not my enemies. And even further, supporting nations who even hate God, as their current national identity.