Something like Cialis or Viagra can provide easily obtainable pumps if that’s what you’re looking for…

I would move away from focusing on the pump as your main goal. Such approach is more suited for people under 30–35. If I’m not mistaken, you’re older than that. At this stage, metabolism doesn’t ramp up to its peak as it used to. You might also have past injuries or chronic joint and ligament issues.

I’d suggest to exclude all accessory arm exercises, keeping only 1–2 basic compound movements. Avoid putting your arm muscles through overly detailed workouts and shift your focus to legs, back, chest, and shoulders instead.

By the way, I want to respect you on your past achievements. A true bodybuilder’s journey starts with their legs.

Lots of variables in play here. You aren’t going to keep the post workout pump for more than 12 hours regardless. Having said that, you should not be looking flatter the next day then you were prior to lifting. It sounds to me like you’re not getting enough nutrients post workout.

Please post your daily diet, including your height and weight plus total macro consumption. Please provide some detail on the amount of carbohydrates. You are consuming post work out and how soon after your work out you are consuming them.

If you are looking as flat as you say you are the next day, it sounds like the glycogen stores in your muscles are exhausted, which would indicate that you are not consuming enough carbohydrates in a 24 hour period after you lift. That will be very detrimental and prevent long-term, retainable gains.

I guarantee your diet is the culprit here, so the more information you can provide. We need to know your body stats as well, such as height, weight, and body percentage to be able to give you accurate advice on what’s your total caloric consumption and macro breakdown should be.

Food is King in this game. Gear is the icing on the cake.

I am using talk to text so Please excuse any typos or obvious incorrect words, substitutions.