There are more fundamental considerations to be made. For example, the small scale structures of the universe might just be too small to be observable by experimental means. As in, not just practically too small (too difficult to build experiments for it), but fundamentally not possible to observe due to their mathematical structure.
There are already a lot of things in quantum physics particularly that we can't observe directly. For example, there's no such thing as observing separate quarks - if you separate two quarks too much the binding energy between them pops another set of quarks into existence. But you can infer their existence indirectly "via math" basically.
However it's easily possible that the more fundamental structures of the universe are bound in such a way that you can't even observe them indirectly, even if you had access to machines that could produce the energies required.
There are already a lot of things in quantum physics particularly that we can't observe directly. For example, there's no such thing as observing separate quarks - if you separate two quarks too much the binding energy between them pops another set of quarks into existence. But you can infer their existence indirectly "via math" basically.
However it's easily possible that the more fundamental structures of the universe are bound in such a way that you can't even observe them indirectly, even if you had access to machines that could produce the energies required.