You are in for a treat with any of the upgrade ideas vs the current Rega. You will find, however, that it is tough to correlate design ideals with reality. For example suspension *should* always be a good idea and direct drive has better measured performance most of the time. Yet it comes down to implementation
All three brands you are looking at have accolades and good history of performance ( AMG being the newest ).
You did not mention the models/ budget you are considering- this alone can sway the answers. Is the SP10R in the mix ?
Did you know there is a current production direct drive also with suspension? It is the Motus DQII made by STST. I sell this brand so won’t say more since I have a bias, but you should be aware of it :)