If you're taking them to fill nutrition gaps, good. If you've refined this based on blood work and diagnoses, better. If you've factored in genetic testing and are slowly applying epigenetic pressure and/or activating pathways to circumvent SNPs related to your testing and diagnoses, this is best.
They are tools. Usually they are fine for fixing something. Sometimes you're looking the wrong way and hit your thumb.
This is like saying diabetes medication doesn't stack with blood pressure medication and doesn't stack with finasteride. It's an unpolished hot take.
A multivitamin is stupid though unless you're basically fasting. About 30% of the population has one or more critical mutations that'll respond very negatively to some forms of vitamins. Without knowing that, you're playing roulette or at least stressing a system or two but feeling overall better because of filling some gaps.
If you're intent on firing in the dark, stick to:
Daily
-D3 + K2
-omega 3 from a source that doesn't sell spoiled capsules
-magnesium, but not oxidate at 1/3 daily requirement
Every Few Days, depending on water consumption
-unmethylated B vitamin
Weekly
-trace mineral supplement that does a few 200%-300% of daily
It's poison if it's rancid. Literal cardiovascular poison that runs through your antioxidants. Also, many people lack the enzymes to metabolize it from vegetable sources.