My two cents: (1) first of all, the majority of the public know virtually NOTHING about Joe's accomplishments. The Democratic Convention is a GOLDEN OPPORTUNITY to inform the public about the achievements of Team Biden wrt the economy, job creation, international relations, fighting climate change, infrastructure, supporting unions, etc. etc. Even with this wide-spread ignorance, Biden and DJT are virtually tied. So don't talk about polls until AFTER the Dem Con.
(2) DON'T waste the convention squabbling about an alternate candidate. Instead pull out all the stops on spreading the story of Team Biden's remarkable achievements. Do this is creative ways, using pop stars like Taylor Swift, arresting short videos, etc. Make a special effort to pull in young voters as viewers.
(3) In addition to highlighting Team BIden's achievements, contrast them with DJT. For example,when discussing Infrastructure do a snazzy video pairing every time DJT mentioned "infrastructure next week" with something actually getting built by Biden's Infrastructure Bill (maybe with a split screen). So, say, 200 quotes from DJT, and 200 clips of Biden’s Infrastructure projects (clearly showing what states they're in.) At say, 3 sec per quote, that’s still only 10 min in all .
Contrast DJT changing a weather map with a sharpie with the climate catastrophes we've all experienced the last couple of years and actions being taken by Team Biden, NOAA, etc..
(4) Push the idea of "TEAM BIDEN". Joe is not running the country all on his own! Introduce members of Biden's cabinet, either with short speeches or videos. Present a lot about Kamala Harris, who is a complete unknown to most of the country. Kamala can address the travesty of the overturn of Roe vs Wade. Highlight the fact that around 40 of DJT's cabinet have refused to endorse him. Maybe get some of them to speak at the Dem Con.
(5) Stress Biden's decades of experience in foreign affairs. Somehow show how America's world-standing has gone from the pits under DJT to immense respect and gratitude under Biden.
(6) Make a strong case for Ukraine, how their freedom-loving story should resonate with all American patriots (and spell out that's it's not costing us much at all, since we're just getting rid of old stock-piled equipment, creating American jobs to replace it.) Maybe have Taylor Swift sing a Ukrainian folksong, and Navalny's widow speak (and BTW their daughter is a student at Stanford). Contrast with DJT’s love-affair with Putin. (They even refer to DJT as “Donald Fredovich”.)
(7) Spell out the threats of Project 2025 (the end of no-fault divorce, the end of contraception, a national ban on abortion even in the case of the woman's health, the abolishing of the Dept of Education, NOAA, and the National Weather Service.,,
(8) Finally Joe Biden should make it clear that if poll numbers AFTER Dem Com show that Joe is still virtually tied with DJT, then he promises to resign so that President Kamala Harris will be the candidate. In any case, Kamala as half of "TEAM BIDEN" will be ready to take over as president at a moment's notice. (Biden could promise, for example, that midway through his second term, he will pass on the reigns to Kamala, giving her two years to serve as President before running for reelection.)
(9) Much of the AV stuff from the convention should be made easily accessible on a website, in commercials, and on TikTok.
In short, give the American people the chance to learn about TEAM BIDEN Only after they’ve had a chance to assimilate this information should polls be given any weight. (Also, focus groups meeting during the convention will give invaluable information about what resonates with the electorate.)