I don't remember who was attributed to this quote, but I think it was Bob Hamman, who at the time could legitimately argue this:
I am not a good bridge player. I am a bad bridge player. It's just that everyone else is worse.
Bridge has got a lot better since then, but it's still true to an extent. It's also argued that a decent A 2021 pair could beat the world champions from 1950 (once. Then the WCs would study the methods, take what worked for them and ignore the dumb stuff, and come back and destroy them). The science in the game - much in bidding theory, but also in play and carding agreements/understandings - improved so much between 1950 and 1980, and then again between 1980 and now. Things that were "the judgement of a master" in the day are now simple enough to explain that they can be taught to low intermediates[#] - imagine what the judgement of a master now is.
The answer is "not even close." It is also "but that's the point, bridge is a game of imperfect information, and removing that breaks the game." It would be interesting to determine how much better a "best play" player would be, given just the information they're allowed to have. Oddly enough, that's one of the really hard things to computerise, though (the other, and linked, one is "how to encode the meaning of the opponents' calls." There's a reason the "World Computer Championships" has such a limited convention chart. It's something that humans are far ahead of computers on, and will be for a long time.)
Unfortunately, we can determine to an extent how much better "god mode", or at least "trying to hide it god mode" is, to normal expert standard. We have records of N- and S-[*] and others who admitted to self-kibitzing; just look at them. There are also, according to Nicolas Hammond, pairs who are colluding - they don't have full information, but they do know partner's hand, and their rates of "concede a trick to DD on the opening lead" and "guess their fit level in the auction" are magic; they certainly take C+ players and make them A-flight.
Agreeing with Joe that a lot of the game as it is played is "take away room to investigate". Against God-mode players, this is totally irrelevant (but would be a searchlight-level flag that they were God-modeing!), so until the normals figured it out, that would also be an advantage. After they figured it out, it would change system completely - and things would move closer. Not close, but closer.
One final thing here - stamina is a huge factor in bridge. The mental effort involved in the game is massive, and whether it is a normal 2-club-games-a-week player in the 6th round of the Swiss (the sixth session in three days of the sectional, after a week at work) or the best in the world on the last day of the final of the Bermuda Bowl (after two weeks of 50-60 hands a day against "the world's best" (even the "no-hoper" teams are still the best in their country, and likely to cruise over most normal fields), mistakes will be made due to stamina failure that just wouldn't be on a normal day. if God-mode doesn't tire as well, that's an even bigger crushing.
[#]A self-quote from elsewhere, parsed for anonymity:
30 years ago without all these shortcut tools, explaining why this is a bad 18 to [a C player] would take pages. Now, you can say "a 6-loser 18 shouldn't be treated as 18, that's below average, and this hand has bad spots and no known fit. I don't think I want to game force with it. Bid 2♥, and if partner raises, reconsider." [I]t would be a hallmark of an expert (as opposed to just Flight A) that they could and did do this consistently, intuitively applying what we can now objectively teach as "90% efficiency" tools to intermediates willing to learn.
[*]I see no reason to add to the permanent stain these players already have. If they are truly repentant and have served their penance, they should be treated as such. If you need to know who I'm talking about and don't, it's all over the 'net.
[**]Note that I'm much less interested in the continued reputation of the ones who were actually colluding (closer to God-modeing) or who "acquired the hands beforehand" or whatever. Especially those who did so not in some random tournament, but in the World Championships. They can yeet themselves into the sun for all I care.