The only issue with mine is tea stains in mugs. Adding salt even when using all-in-one tabs does seem to be the answer but a pain. The Fairy tabs do seem the best for use without salt in my experience. My Bosch is some 17 years so only has three manual programs.
Tea stains seem to be the problem for me too, in my 2004 Bosch.
The salt reservoir is set at the mid-point, as is the rinse aid dispenser (soft water area). I always use the hottest programme, 'Auto Super Wash' which is supposed to be at some temperature between 60°C-70°C.
I use 'Clean n Fresh' or Lidl's (when available) dishwasher cleaner liquid, in the one-shot bottles. This is an acidic formulation (citric acid and sulphamic acid combination).
It doesn't matter which detergent tablets/pods I use, tea stains seem to be persistent.
Finish Quantum gave a lovely lustre to the crockery - but the stains remained. Fairy leaves everything with a weird lemony taste, stains still there. Finish Classic leaves a powdery residue and stains.
According to the machine's manual, phosphate-free detergents might be to blame (they've less oomph than the old phosphate formulations).
It also says in the manual to use the hottest wash and extra detergent to combat tea stains.
I've tried one tablet, two tablets, three tablets. I've tried one Fairy pod in the sealed dispenser, and two cheaper tablets on the floor of the machine. Generally produces a clean load - but mug stains still remain.
I tried Finish powder a few years ago, but they'd fiddled with the formulation for that too, and the whole load - and the dishwasher interior - were covered in a white powder.
Finish Liquid Gel lost the white, phosphated, chlorine formulation - and became an insipid, bleachless, blue-green, non-phosphate formulation. When I complained to Reckitt-Benckiser, I was told to use the tablets for tea stains. Apparently the EU was to blame for a directive causing detergents to be changed.
One thing I will say: Fairy seems to create more foam than most of the others, and the machine does struggle with the suds. I read that this is possibly worse for modern Bosch, Siemens, Neff machines, as they now have the heater element incorporated into the circulation pump assembly... which they call the 'heat-pump'; i.e expensive to fix.