The trouble with Vitamin D is afaik, as with some other vitamins, that it is fat-soluble rather than water-soluble. So the excess of the Vitamin won't be flushed out through the urine - but rather accumulates in the fat. At some point this accumulation may lead to toxicity ("Hypervitaminosis D" [1]).
Personally, I dose 4000-5000 IU D3+K2 in the darker seasons and that has been working well for me.
Vitamin B12 is water-soluble and therefore should not cause accumulation in healthy people.
I did that every day and started to have muscle pains and weakness after a while. After doing some research and experimentations, turns out you also need to take magnesium if that happens.
I can say, as an anecdote of one, that I have been taking 5000 IU of D3 along with K2 and Magnesium every day (almost) for about 3-4 years, with no ill effects and what I believe to be a positive effect, in that I have not been ill at all during that time. Cold, flu, anything.
My beginning D3 levels were 39 ng/ml, so just under the ideal range of 40-60, and not really deficient. I have not tested recently, though I believe my numbers would be higher now. I also try to get at least 30 minutes of sun exposure over most of my body 3-4 times per week. Fortunately I live where I can get good sun exposure year-round. Point is, test your serum D3 level and do whatever you need to get into the desired range, and don't take more than that level of supplementation. I do believe that sun exposure is a better choice than supplements, if practicable.
That sounds like too much, which can cause calcium deposition in soft tissues. I'm 250 lbs / 113 kg and only take 125 μg (mcg) of D3 and 100 of K2 MK-7 once every other day (qod) because of D status for COVID prophylaxis and chronic premature distal osteoarthritis.
Calcium, magnesium, sodium, and potassium in balanced amounts along with K and D maximize bone health. Alkali metals supplementation alone is rarely a good idea because of the often common transports and osmotic competitions.
In general, a multivitamin, b complex, and omega 3 in the form of canned fresh sardines or anchovies (fish oil capsules are typically low in actual 3 and high in 6) is probably enough for most people.
5-10 mg/day of extra zinc during the annual cold season is fine too.
Don't supplement with E without a specific medical need.
It's my understanding that oral availability is lower than IM, and that people who are deficient get 70,000 IU injections.
I'm entirely untrained, but my amateur evaluation of the situation leads me to take 50,000 IU orally once each week or two. I imagine that twice that amount would be fine, too.
Personally, I dose 4000-5000 IU D3+K2 in the darker seasons and that has been working well for me.
Vitamin B12 is water-soluble and therefore should not cause accumulation in healthy people.
[1] https://en.m.wikipedia.org/wiki/Vitamin_D_toxicity