Judge, despite being a warrior, was more of a scientist, and also wasn't genetically modified like his sons, so he should be weaker than them, right? I loved Germa 66 and I hope to see more of them in the near future (at least one serious fight for each of them), and I estimate the brothers to be close to Katakuri/Marco's level. We are lacking feats so I could be enormously wrong.
Correct me if I'm wrong (I haven't reread those chapters since they came out so I could be), but wasn't Judge about to get his ass kicked by Sanji and only beated him in return because he shielded himself with his clone army and Sanji hesitated hitting "bystanders"? Before he knew they were clones designed to follow every orther from Judge. Even a suicide order.
You are right. He took advantage of Sanji's compassion and won the battle. If that fool has no meatshield or raidsuit then Sanji would win. I would argue Sanji can win even if Judge had his Raidsuit and Sanji without.
I am confident Sanji can kick his ass one way or another. Another important thing to note is the reason why they fight. If it is for the Strawhats or a woman, Sanji will get all fired up and diable jambe til this fucker melts in his suit. Sanji actually has a very durable body. Even when he lost, it didn't really seem like a loss to me. It felt more like something along the lines of...this is getting fucking stupid, this old fuck is just some rich brat with gadgets, I'm just gonna lay here and not waste any more of my skills on this boomer cuz he aint listening. Honestly it just seemed like Sanji was over it. Hahahaha fucking boomers I swear they get annoying af sometimes and we all know what I am talking about.
But on the flip side of things, with age there can be wisdom. Wisdom to exploit others' weaknesses. And wise as he is, I wonder how much Judge experimented with himself. If he has any types of crispr-like genetic augmentations in addition to his raid suit. He knows his genes suck. He wasn't born like Ace who fought adults at a very young age. That is why he needed to enhance his kids because otherwise, they'd suck too. Sanji seem to be the lucky one to have not inherited his bad traits. So I think it may be unsaid but it is safe to infer that Judge personally has some kind of genetic augmentations too albeit done to himself later in life. Vegapunk might even have helped just to gather some useful data.
Either way though, Sanji would still kick his ignorant old ass. when Sanji stood on that table to rescue his family because his brothers were too stupid to, instead of talking to Judge he should have just kicked him in the face enough to give him a makeover like he once did with Duval back on Sabaody or whatever.
To answer the question though, Judge is probably a weak captain tier. Stronger than Brownbeard but weaker than the Funk brothers. Half as strong as Bellamy. Yeah I might be biased here but I really don't think Judge is that tough. Just because like I said, I didn't feel like Sanji really lost. He wasn't even fighting that hard like when he fought all the other baddies. And no Judge is not as strong as Vergo.
And I also have to disagree with the brother's strength too. They are not even close to Katakuri or Marco. For oneKatakuri and Marco is not bogged down by any stupid programming. And two those two do not need a raidsuit to overwhelm their opponents because they are such great beasts in their own right already. And if Katakuri and Marco fought the brothers with their raidsuits on they will still lose. The reason is simple. If your base is strong and you add a suit on top, that person will just be even more powerful. Granted they are genetically modified but I don't see them not overtly relying on their raidsuits so therefore they may be genetically enhanced but may not really train their base forms before donning their suits of shiny armor. Of course, they do not get enough screen time for me to know for sure but it makes sense to me. I can hear Katakuri laughing being compared in strength to these Germa clowns. Don't get me wrong, the whole concept of Germa is great but Judge is a dick. I mean come on with a name called Judge, you have to be a fucking asshole lol.