Nicolas Maduro is the one opposed to sanctions relief.

Think about it: sanctions are just the perfect justification. There's nothing quite so flexible, encompassing and revolutionary as being the target of U.S. Treasury sanctions. Everything can be explained under the purview of sanctions. Lack of food? Unemployment? No gasoline? Derelict hospitals and crumbling infrastructure? Malnutrition? Teachers striking? Power cuts? All of that, and more, happens because of sanctions. Like the Cuban dictatorship, chavismo has not lost, but reaffirmed the credibility of its now 24 year old criminal regime thanks to sanctions. It no longer has to blame "the previous government", i.e. itself. Now it can "convincingly" blame U.S. sanctions, forevermore, and Nicolas Maduro is the first one who won't give up that Trump card easily.

Sanctions open BRICS' doors. Sanctions would get a rogue regime audiences with the likes of Xi, MBS and Putin. Sanctions would align chavismo with Modi. Sanctions would facilitate  trading with Turkish companies close to Erdogan. Sanctions would make the world's dark fleet's owners salivate at the prospect. Ditto every single trading house and bank in Switzerland and other money laundering jurisdictions. Sanctions equal opportunities aplenty for non-U.S. parties and governments. Sanctions make Chevron do Maduro's bidding. Sanctions are a victimhood cloak for chavismo. Sanctions accelerate moving away from the U.S. Dollar and push the U.S. further into isolation. Sanctions are a headache for whoever sits in the White House. Sanctions get empathy towards "the glorious revolution" all around Europe. Sanctions, ultimately, work against U.S. hegemony.

Maduro knows this. He is the biggest obstacle to purported negotiations and gains absolutely nothing with sanctions relief. Can anyone possibly think he is about to relinquish all of that for "free and fair elections" in Venezuela?

Recent news reports claim the Biden administration is about to lift sanctions provided Maduro makes some political concessions regarding coming elections. Maduro's concessions have been to disqualify opposition candidates, appoint the official who did so to head the Electoral Council, throw legal impediments to coming opposition primary elections, and ordering the State telecom and internet providers to block access to websites with information about primaries voting centers.

Elsewhere, Venezuelan debt holders are already spending the potential windfall that sanctions relief could represent. This site is of the opinion that Maduro, who plays the long game, won’t concede anything that imperils his grip. The following question would be whether Joe Biden is prepared to lift sanctions in exchange for nothing. Considering Venezuela's irrelevance, that too is unlikely to occur.