Can't decide on Integrated Amp - Please Help

Hi, really trying to find the best deal I can on a used integrated amp. My current set up is

Monitor Audio RX6 speakers
Oppo 105

Looking for a strong integrated that if I wish to upgrade my speakers will easily handle the change.

Looking at spending no more than $3,000 for a used example and would love some help. I stream most of my music through the Oppo instead of CD's and listen to a lot of Pink Floyd, Dave Matthews, Sting etc

Few choices i have outlined and really hard to be able to audition anything and would like it to match the speakers and Oppo well

Rega Elicit - R
Krell S550i
Hegel 200 or 300 if can afford (is the DAC much better than the 105)
Stello ai500
Saw a PLINIUS HAUTONGA Intergrated A but don't know too much about company.
Modwright 200

My room is around 15 x 15 with wood floors

Thanks in advance for help