I read your other post as well.
Getting back to basics.
Espresso requires a 25-30ml extraction of coffee from 7g of coffee [60ml & 14g for a double] at 95C and 9 bar of pressure.
In a true espresso machine the 9bar pressure is generated by the puck and is a combination of dose, grind and tamp pressure.
Pressurised/creama enhancing baskets have a squirty hole and essentially this creates most of the pressure [rather than the coffee],
So in that sense they are forgiving of inconsistant dose, grind and tamp.
But this is relative, in other words the "window" to get this right in a non pressurised machine is much much smaller than for a pressurised machine. You will still get some variations in a pressurised machine though.
You do not really say what your inconsistancies are other than maintaining "consistant crema".
What do you mean by this?
Are you getting the right volume in right time?
How are you managing the brew temperature?
Are we talking back to back shot inconsistancies or AM vs PM differences?
There are many factors to consider:
Really fresh coffee [less than 4 days post roast] can produce a very "enthusiastic" crema due to the excess of gas.
So you can get a very foamy gushing creama that doesnt settle neatly into a shot.
Old coffee [say > 20 days] will produce weak crema.
For consistant repeatable shots, you need a consistant dose, grind and tamp.
Dose is the least talked about, but is the hardest to achieve and probably the most important as it forms your starting base.
It involves getting a consistant ammount of coffee into your PF and how/how well this is achieved is totally in your hands.
The focus of tamping is usually about consistant tamp pressure [eg 13Kg] but I believe the "quality" of the tamp [ie creating a perfect puck without cracks channelling etc] is more important.
So, All of the above is your responsibility.
Next comes grind, a good grinder will simply produce a consistant and even grind and it will have repeatable adjustability to allow the grind to be changed as necessary [this will change throughout the day]
If it cant do all of this it will contribute to inconsistant results.
Then comes the machine, if all the above is right then [assuming a basic boiler machine] your only challenge is to develope a process to pull the shot at the exactly the right part of the cycle.
Once this is down, you should get consistant coffee.
It all sounds easy, but its a long chain of dotting "Is" and crossing "Ts" requiring a confidence or trust that each step of the way is right.
Sloppyness at any point will ruin the outcome.
So in line with your original questions,
If you want more consistant coffee you need to always be mindful and self critical of your technique, when you feel confident that its right, you can you can then look at the grinder.
Based on "the vibe" of your posts you are probably never going be 100% confident/trustworthy with the Krupps grinder so I suspect you are already looking to upgrade it.
If you also want better coffee and are prepared to put in the efforts,
I would recommend purchasing a non pressurised PF/Handle for the V V.
FWIW, I believe a shot produced by a pressurised machine will only approximate a true espresso shot and in comparison will have no body, a thin watery mouth feel and weak flavour. Call it 10% as good
Therefore, the quality gain with a new grinder and pressurised filter will be large.
Best of luck with the coffee journey, keep us posted.