As a matter of principle, I am totally against simplifications. Either play the original piece – or if that is too difficult for you, play an easier original piece.
99% of the piano repertory is actually quite easy – and very beautiful.
Have a look here:
https://pianoforum.net/smf/index.php/topic,4140.msg38111.html#msg38111https://pianoforum.net/smf/index.php/topic,4416.msg41105.html#msg41105https://pianoforum.net/smf/index.php/topic,2562.msg22127.html#msg22127Something similar to what Daniel is suggesting (a collection of original pieces in progressive order of difficulty) can be found in the several ABRSM publications:
Collections:
Baroque Keyboard pieces – Edited by Richard Jones
Five volumes going from easy to advanced.
A Keyboard Anthology (first series) - edited by Howard Fergusson
A Keyboard Anthology (second series) – edited by Howard Fergusson
A Keyboard Anthology (second series) – edited by Howard Fergusson
There are five volumes in each series covering grades 1 – 8 and sampling all musical periods.
A Romantic Sketchbook for Piano – Edited by Alan Jones
Short romantic piece for piano – Edited by Lionel Salter
More romantic pieces for piano – Edited by Lionel Salter
Five volumes in each collection again in progressive order of difficulty. Take the “romantic” in the title with a pinch of salt. It refers more to the character of the pieces than to their actual time period.
Original pianoforte pieces – These are a selection of pieces used in the ABRSM exams over the past 60 years.
Easy piano series – This is an amazing collection now with more than 100 albums, each dedicated to a single composer, and having 20 or 30 or their easiest pieces. Chopin, Liszt, Bach, you name it, they are all represented there. All pieces are original and all are expertly edited with excellent fingerings and authoritative realised ornaments.
You can get more details from here:
https://www.abrsmpub.co.uk/publications.htmlYou may also try “Classics to Modern” and “More classics to moderns” both edited by Denes Agay. Each collection has ten books in progressive order of difficulty, all are original pieces by many known and not so well known composers.
Most music shops have these collections or can order it for you.
Best wishes,
Bernhard.