If you follow the daily dosage information, you won't even get near harmful levels of vitamin d. Recommended is about 600 IU daily. If you take 60.000 on a daily basis for months, you build up toxicity.
For that you typically need to take 30 pretty strong 2000 UI pills on a daily basis for months, while ignoring the label that states each pill is typically 250% of the daily recommended amount, and the instruction which notes the tolerable levels max out at just two daily pills.
Toxicity is extremely uncommon. Whereas deficiency is extremely common. Up to a billion people are expected to have some form of vitamin d deficiency.
That's not to say it's not a problem, but rather that it's very rare, nothing like say an opioid overdose problem. As with all things, balance is key. You can overdose on 5 cents of water in the span of 5 minutes. Acute vitamin d overdose is known to happen if you take something like 300-1000 pills of 2000 UI over a period of days, which is pretty insane.
“ It also estimated that 8895 IU of vitamin D per day may be needed to accomplish that 97.5% of individuals achieve serum 25(OH)D values of 50 nmol/L or more.”
So I am skeptical of supplements as a rule. Of course there are a couple of odds, like iodine, which is so beneficial to supplement in general community, that it is added to table salt as default, you only skip if you have specific conditions like thyroid problems.
I wish there were more research or comments on possible harms and disadvantages of excessive use of vitamin D, than I think I could more easily decide to use.