I think Op. 10 No. 5 is a step up from the Liebestraum, and is about equivalent to an easier Prelude, in my opinion.
For you, I would recommend you stay far, far away from his Etude-Tableaux, as far as I know they are all mature, extremely difficult pieces and are not to be trifled with.
However, many of the Preludes are quite accessible. IOp. 23 No. 1, No. 4, No. 5, No. 6, and 10, and Op. 32 No. 2, No. 5, No. 10, No. 11, and No. 12 are more accessible technically (but they are certainly not without their challenges!). If you more ambitious, look at Op. 23 No. 2, No. 3, 7, and 9, and Op. 32 No. 1, 3, 6, 7, 8 and 9. These are the more difficult ones.
Op. 23 No. 8, Op. 32 No. 4 and 13 are all very difficult, taxing, and mature music works, about comparable in difficulty to an Etude-Tableaux.
My personal recommendation for you would be Op. 23 No. 1, No. 10, or Op. 32 No. 2, 11 or 12. These ones are the easiest, in my opinion, and you can't really go wrong with these ones.