If these are in the public realm (over the road/pavement areas) then this is likely to be a discussion between the relevant infrastructure companies (e-redes, whichever telecoms companies) and the câmara municipal, or if the road is more major, Infraestruturas de Portugal. Independently of cost, they would be the ones with the relevant rights, responsibilities and liabilities, now and post-changes. Your view will be a lesser consideration, and I do not think you would have any particular rights in this context.
It might be sensible to start either by speaking to the lawyer who assisted in your purchase, if you were happy with them; or an informal discussion at the câmara to assess their interest in cooperating (with a sympathetic Portuguese speaker, perhaps).
If any other private land is relevant, you'd substitute the owner(s) for the câmara.
Ultimately, there is no right to a view - I know you're not asserting that, but it means there may be limited sympathy relative to the work and future liability issues involved. Cables are aerial throughout Portugal, so you're working against the norm, rather than suffering from a particular disadvantage. I mention this to manage expectations, and also because your desire for a view may meet with limited sympathy, and so may not be the key thing to play on.
(I have sympathy - we would also have a much better view were it not for a multiplicity of cables on our immediate horizon. With each neighbour having at least one electrical and phone line, as well as the main high tension supplies, passing over a mixture of land ownership, there is zero chance of anything changing, sadly!)
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