How is your cartridge setup - the tonearm TA-RB880-RETAIL-UNI.pdf (rega.co.uk) does not show the ability to alter the vertical tracking angle (VTA) which for a high end cartridge such as the Paua II can be critical to get the best results. Can you set VTA? Viewing the telescoping aluminum cantilever which has a flat spot where the stylus is inserted, is that flat spot level or tilted with the record? Each position will yield a slightly different sound quality. Tilted too far fwd "will tend to have good stage width but the strings will sound unnatural, edgy and irritating.". Tilted too far back "the sound will be slightly muffled, with a lack of high frequencies and air around the instruments." Sedrik Harris: Setting Up Cartridge VTA (enjoythemusic.com) . Others on this forum can fill-in with more details and there are many articles on the web on VTA.
What loading do you use with Travish? The maximum is indicated as 500 ohm which would be the 'normal' minimum (470-ohms actually); lower would cause some high frequency roll-off. Have you tried running at 400-ohms? Also, have you tried tube rolling? The Travish manual Microsoft Word - adagio_owners_manual_rel6.docx (shopify.com) implies its using new current available tubes - not New Old Stock (NOS). Some NOS tube(s) could make a huge difference. Check with Travish to see what tube or tubes will have the most musical impact; and then consider some NOS for that or those tubes.
Just some thoughts. Good luck.