On any, the embouchure is very different from trumpet, especially flute - which may well be the cheapest option, and smaller easier to carry, etc.
Clarinet in B♭ is a good option - same sort of range as trumpet, and uses same music, as both are transposing instruments, so you can play off your existing dots.
It's also not too different fingering wise ...
Yes, clarinet or alto sax are probably the easiest woodwinds. But you'll be playing much the same sort of part you did on trumpet. Flute is portable and will open up new musical horizons. Get good and you'll be in demand too. The world is overflowing with clarinet and sax players.
Among woodwinds, clarinet and flute have the most varied repertoire. Much more than oboe, subcontrabassoon, ocarina, etc. Flute embouchure may be more foreign to you than the clarinet's.
Also, as a transposing instrument, clarinets are closer to trumpets (B flat is common) than flutes (C, G). So, clarinet.
Put it in a warm bath, blow the water through, clean it with Sigolin or another (not sharp) cleaning product. Is it silver or bronze? The product may depend on this. Well, there are special (prepared) cleaning towels. But they are only available in a music shop where they can give you further advice.