Minoxidil on its own is usually weak, but using a Microneedling device once a week + Minoxidil topical Liquid is a whole lot more effective. Studies shown it was about 3 times more effective than Minoxidil alone.
Regarding DHT blockers or Finasteride/Dutasteride, I personally would recommend that you do not use those until you have tried Minoxidil + Microneedling for at least 6 months and are still losing hair/seeing no significant improvement or at least maintenance.
I say this because:
1) You said your hairloss is not so bad yet.
2) If you can avoid taking something that can very possibly cause negative side effects some of which could potentially be permanent, then you should.
3) People are talking about Minoxidil stopping working after stopping use of Minoxidil - to that I say, literally every non-surgical treatment we have will stop working after you stop treatment (including Finasteride/Dutasteride) - so might as well try the less dangerous treatments like Minoxidil + Microneedling.
Regarding vitamins, they are important, they won't stop your hairloss (unless the reason for your hairloss is primarily due to a vitamin deficiency) but it will help to strengthen hair and make it more healthy and grow faster. It's not a cure ofcourse but hair loss treatment requires a multi-faceted approach so making sure that you are taking all the essential vitamins are only a benefit. It's better to have it than not.
You can try Microneedling + Minoxidil 5% Topical Liquid for 6 months atleast, take your vitamins, do scalp massages (this doesn't stop hairloss but it does help with blood circulation to the hair follicles which is often overlooked) and also work out atleast 4 times a week, it also helps with getting blood circulation flowing everywhere and keeps your body running more efficiently.
If you don't see any maintenance atleast after 6 months, then you can consider using Finasteride if you decide to.
But hope is not gone, we're almost in 2022 and the company Kintor Pharmaceuticals should be releasing their drug called Pyrilutamide in 2023 which is said to be a more safe and effective alternative to the current hairloss treatments.
There's also quite a few treatments coming out not too long after that so it's not like you need to be thinking your current regimen for example Minoxidil + Microneedling needs to last you for even 5 years, when we are likely to see treatments in 2023/2024 like Pyrilutamide or Breezula, HairClone, etc.
You just need them to buy you about 3 to 4 years till Kintor Pharmaceuticals drug GT20029 comes out which is highly anticipated to be great treatment.
HairClone UK CEO said that they plan on starting treatment in their clinics and partner clinics in the UK early next year. That treatment supposedly will thicken and strengthen hair, provided there are still hairs and aren't too far gone which is quite interesting and a good step for maintenance whilst we wait for a cure.
But IMO, if we get treatments that provide solid maintenance + scarless surgery (verteporfin) + hair transplants = closest thing to a cure.