Standardizations and lower costs through economies of scale are great. However competition is also good, as is redundancy. Some strategic redundancy is also a good idea so the whole European defense doesn’t collapse because of something like Brexit or Orban in Hungary.
The requirements snd budgets for the armed forces vary significantly depending on the geography and infrastructure of a country and likely missions.
Having a military with diverse equipment means the enemy will have to learn about more systems and how to fight them.
Rifles make up a small part of the budget. Buying some weapons locally make them cheaper for the state as the money spent goes into the local economy and some of the cost flows back to the state in the form of taxes. So buying more expensive local weapons can be cheaper overall than importing a seemingly cheaper weapon.
Run it locally using https://lmstudio.ai/