You caught me there. There used to be art connoisseurs who favoured the aged look in old masters but one doesn't hear so much from them these days. There are some impressive YouTube videos on art restoration, including good ones from the NY Met. The artist never intended the pictures to look dull, so I am in the 'restore them' camp, though there are too many examples of poor restorations of old masters where important glazes have been taken off and the modelling badly affected. I have an artist friend who is a painting restorer and I have seen her at work, though she specialises in Tudor paintings on wood rather than later oils. It always seems miraculous to me.
There's a fine collection of maritime art to be seen in Hull; or there will be if ever the authorities get around to re-opening the buildings housing it.
Sadly, my visits to Hull have all been on business with no time for wider exploration. Although one encounters some horror stories about the cleaning and restoration of paintings, I thought the results in this case were remarkable - perhaps especially in the case of the whaling ship Diana trapped in ice - and worthy of a note here. It seems that re-opening of the Hull Maritime Museum is expected in 'early 2025' (NEWS | Major refurbishment work to Hull’s Maritime Museum gets underway | Maritime Hull (en-GB)).