Can’t speak to the level of upgrade the Rega to Thorens would be, but an upgraded phono would definitely be a worthwhile move regardless. I also have the Leben 300xs, went from a Schiit Mani to a Darlington Labs MP7 phono and was thrilled with the move. For the Hana just add their SU-7 active head amp or an SUT and you’ll be set.
The Gold Note PH-10 seems to show up on the used listings at least one a week for decent price.