Most people unless exposed to regular decent amounts of sun, will need a Vit D supplement, a simple test can check. You need to be careful of taking fat soluble vitamins when you don’t need to as you can’t excrete excess, and iron shouldn’t be taken without a blood test as of you don’t need it, it can cause toxicity. Same with selenium, deficiency in either can cause tiredness but test before supplementing.
Multi vitamins aren’t the best in my opinion, you can search studies on their effectiveness.
