Supplements and vitamins?

Personally I have felt the benefit of protein / carb drinks after every workout - but then I eat very little meat so that may be why. For me, it really is a direct relationship between aches / no aches.
I dont know about multivits, but its probably true that if you exercise a lot, you'll need more than if you are entirely sedentary. How much more? Do you already get enough in your diet anyway? Thats a good question.
What is 'a good diet'? That can be controversial too. If you listen to the Paeleo diet people, they wouldn't agree with the current perceived wisdom of what we should be eating.
Good stretching post workout also helps me.
I'd also echo the advice of 'get plenty of rest'. During the later stages of sleep is when you release HGH which repairs and builds muscle. Short nights of sleep don't allow you to do that.
If you want to be able to go 'another gear' I'd say there are two things you'll need - one, a good FTP level, and two, a well developed ability to spin the legs up to a high speed and develop a lot of power, whilst flushing out the lactic acid efficiently. So that would be lots of long, slowish aerobic training for one) and lots of intervals for two).
But, you probably knew that all anyway!
Good luck.

A page of sales guff isn't a peer reviewed paper.
That's no better or worse than someone linking a page from a multi v manufacturer on the benefits of multi v's.

Unless someone is genuinely deficient in essential vits and minerals then taking multivitamins is a scatter-gun solution looking for a problem. On top of that, they invariably use processed (and often synthetic) sources.

https://www.precisionnutrition.com/food-is-not-fuel

Protein supplements/bars/drinks - avoid, unless you're on a vegan diet and need to up your protein intake, or are doing some serious damage in the squat rack.

Balanced, nutritious diet, hydrate lots, rest lots and what Le Grindeur said about targeted, intelligent training.

Re. diet - it depends what you mean by "pretty good". Lots of people think they eat well but often in reality they don't.

IME the persistent dead legs feeling is often related to inadequate rest or poor sleep. Powders and vitamins won't fix that.

They won't give you an extra gear anywhere either. Being able to ride hard or accelerate on climbs requires a really good level of fitness. It's easy to underestimate how long that takes to develop.

Get some beetroot in yer.

I'm not a huge proponent of supplements to be honest, but you could try magnesium salts. Pour several handfuls of the salts in the bath after a hard ride, or you can buy magnesium oil in a spray (it's not cheap though). There is some scientific evidence of its (varying degrees of) efficacy out there.

One thing I know that works for me if I start feeling fatigue generally is Floradix (either tablets or the liquid - definitely an acquired taste). It's very easily digestible iron, as well as other nutrients and minerals, in an entirely 'natural' form. Iron tablets in themselves mess with people's stomachs and aren't digested well anyway. Might be worth giving it a shot and seeing if it has any effect. Even a small iron deficiency will affect your performance, recovery, and general feeling of fatigue.

try my protein . com lots of supplements at a good price

Deadness and aches are from lactic acid. Simply, you're riding too fast for your level of fitness. A heart rate monitor (or power meter if you're rich) will help you get the effort level correct. Heart rate zone 3 will see you produce lactic acid, so if you keep below that you'll have less aches. Ditto threshold power (I think - I don't do power) Rather than take supplements, just work on fitness so you can minimise lactic and maximise recovery ability. Long slow rides or intervals will see you make gains. Have a google for advice on programs and methods to maximise this for your time constraints and whatnot.

Personally, I used to take multi vitamins, fish oil, chocolate milk for recovery, creatine protein shakes etc etc. Never really made much improvement. Last summer I spent 6 weeks HR training and started getting PRs on all my Strava segments. My average training ride went from 40 miles to 80 miles as I was able to spread the effort sensibly.

Best of luck

if, like me, a coffee addict, then hold off on that for 36h and just before ride slam ~200mgs in..perhaps 1 large cup of strong with no milk. i bet youll fly. equally do the 1day carbo load in parallel...breakfast of porridge etc... stick to rice then for lunch and dinner (about 600g of it). you'll have found your extra gear i reckon.

beyond that you can try the old nitrates, creatine, blah blah...cant say that they'll make much difference though - however, no particular experience in that area.

alternatively lose a kg will gain you 10 watts up a more than 5% gradient