You might try Nizoral shampoo if you can find it. Leave it in for five minutes.

Often what people call "dandruff" is not actually dandruff. You might have dry scalp, which causes flakyness and the dandruff shampoos do nothing to help (I'd argue they even make the dryness worse!)

In my case it was dandruff and what made a huge difference is to wash twice in a row (lather, rinse, repeat). I leave the shampoo in my head for a bit on the second wash while I do my other shower business.

That doesn't sound normal if you are looking for comparisons tbh

Do you also have a dry skin?

Got rid of my dandruff problem when I realised that I was sensitive to SLS compounds. Try to use non-sulfate products for a while.

... and I no longer need to use skin lotions on a daily basis.

I used dandruff shampoos for most of my life. My dandruff is the best it's ever been since switching to a shampoo and conditioner that are slightly acid of neutral instead of basic like nearly every other shampoo.

Your skin is meant to be slightly acidic. Constantly assaulting its pH is not ideal. Yes it reasserts its normal pH pretty quickly afterwards but being gentler with your skin can help with some issues.

I'll keep it short: no, there is no "healthy" amount of dandruff. Definitely look beyond the 3-in-1 combos, those can really make things worse. And if that doesn't work, ask a doctor, since dandruff can have a number of different causes.

Aleppo soap finally resolved it for me after years of fighting the yo-yo effects of medicated shampoos. It's just an old hard Castile soap made using olive and laurel tree oils. Laurel tee oil is apparently pretty good for skin, and works fine to clean your hair.

I don't go in for woo, but it is kinda fun to be using a soap recipe that goes back a couple thousand years. Mileage may vary of course, but I've found it to work extremely well, and as a bonus has a pleasantly neutral smell—herbal as you might expect. 20% or so blends of laurel tree oil seem to do the trick.

Go to the doctor and get a diagnosis.

Then look for a solution.

There are only a few options for some problems.

I had this issue for years and finally tried just plain head and shoulders. Once the bottle ran out I went back to regular shampoo and conditioner and I only wash my hair 3 times a week now. The dandruff never came back.

Look up the "no poo" movement. It's been over 5 years since I washed my hair and it's the best it's ever been.