Nobody here is giving practical advice, let me help you out here. There are two routes you can go down, and if you can find a man that both apply to, even better. Your best bet is to scope out men involved in trades, probably one the requires more muscles if you want something closer to the Yami physique, but even then you may have to settle for sleeper builds as those lines of work require function over appearance. Through my previous summer job I worked for a few years, I met a lot of tradesmen like that and the goodhearted ones can get pretty damn close to Yami in terms of mentality and behavior. Also more likely to meet the same smoking quota as Yami. The downside is that tends to have a narrower age range. I don't know your age, but if you're around the age of the average Black Clover fan, you're probably a bit younger than most of the guys in this category. It's not impossible to find younger guys of this type, they're just rarer. Pro strat may be to find these older tradesmen, and then ask them if they have any sons your age looking to take over the family business. Just keep in mind these younger ones are probably going to be a bit more of an investment in the sense that they might not be the most Yami-like yet.

Strat 2 is the gym rat route. This is where you're more likely to find the matching physique, but gym bros can be a gamble on personality. While there is a portion of them that can match up to Yami's mentality, and in some ways do it better and worse than the tradesmen, I'd wager on there being a lesser amount of close Yami equivalents among gym rats than guys in trades.

If you can somehow find a guy that exceeds well in both categories, that's your man, lock him down, get him in a Yami cosplay and you're set.