New Turntable Direction

6k doesn't make sense.....unless you are going Keel Radical etc....Upgrading to Lingo 4 plus a Karoussel bearing will bring your turn table to another level,,,,can add the Kore sub for an extre 1k. Total for all this would be 3.5 k minus the sale of the Cirkus and the Lingo 800-1k....Let say a net cost of 3K.....would be hard to get a better turntable.....

Work around the cartridge, different cart = different sound...

I’ve been using a VPI HW for 35 years. MK II at first, then upgraded to MK IV. With an MMT arm and a Koetsu. 
Best to avoid letting those marketers get into your brain and scratch your itch. If it ain’t broke... my two sense. 

Well I have to agree with the 301/401 and even Lenco suggestions.
I have all three and a VPI, Artemis labs and Yamaha GT-2000...I know.

Theer is something really organic, natural and my ears immensely pleasing about the 301 and 401. I bought two in ok shape with need to replace several readily available components.
I am not a very handy person but was able to do a bunch of stuff myself, add a nice Ortofon arm and some vintage cartridges.

The VPI Prime with Ortofon Cadenza black and Auditorium SUT sounds incredible. But just different. I use Shindo entry level components and DeVore O/96 or Altec Flamenco mainly.

If I would need to give up several TTs I would keep the 301. BUT honestly I am biased towards vintage gear (have many vintage tube amps/systems) cars, etc...

I think the OP needs to find a way to listen and decide as there are so many wonderful modern options as well that it is hard to chose.
Like an entry level Kuzma or PEAR Audio can be really great.
As well as many noted above.

I would suggest to start with cartridge upgrade first. In vinyl playback cartridge is responsible for 70% of sound, phono preamp for 20% and only remaining 10% are dependent on table/arm combination. All this of case when we you are dealing with real high-end gear. Thus cartridge is the component where you can have most improvement or simply change in sound, if this is what you are after. What cartridge change does not produce further improvement, you can proceed with upgrade or replacement of phono preamp. Only when you still want to get  a notch higher - you should look at new table/arm combination. Of cause when you are selecting cartridge, make sure it is compatible with your arm (height, weight, suspension flexibility are all important in that).