ATLANTA — Cardi B isn’t just talking that postpartum boss talk — she’s walking it, straight into a New Jersey gym just days after welcoming baby boy Brim with NFL flame Stefon Diggs, cranking out a sweat-drenched cardio session that has her looking like she never skipped a beat (or a burpee). The 33-year-old “Up” icon dropped jaws Thursday with a no-holds-barred IG Story montage of her StairMaster marathon, rocking a barely-there sports bra and high-waisted leggings that hug every curve like they’re on payroll, her caramel skin glistening under fluorescent lights as she powers through 30 minutes of pure hustle. “Little Miss Drama” tour prep is in overdrive, folks — and if Cardi’s abs are any indication, those February stage stomps are gonna be seismic. But not everyone’s cheering; the snap-back shade is flying faster than Offset’s baby-daddy denials, turning her fitness flex into the latest battlefield in the endless war on women’s bodies.

The footage hit like a plot twist in her already chaotic mommy era: filmed at a sleek Edgewater spot overlooking the Hudson (because why not add skyline envy to the workout envy?), Cardi hops on the machine at dawn, ponytail swinging like a metronome, blasting what sounds like a remix of her own “Bodak Yellow” through AirPods. No trainer in sight — just her, the machine, and that signature Bronx grit, climbing like she’s scaling the charts. By minute 15, sweat’s beading on her forehead, but she’s grinning that megawatt smile, pausing only to chug from a neon-pink Hydro Flask labeled “Brim’s Mom Boss.” “Y’all, this is day three postpartum and I’m feeling like a million bucks — no weights, no drama, just me getting my mind right for the stage,” she captions one clip, zooming in on her reflection: toned arms pumping, a subtle post-baby pooch that’s realer than most influencers’ “relatable” reels, and zero apologies. The montage ends with a triumphant fist pump and a mirror selfie, her glow so fierce it’s got filters begging for mercy.

Fans? They’re feasting. The Stories racked 3.2 million views in hours, with the comment section erupting into a hype parade: “Cardi out here making postpartum look like a vacation! That energy is EVERYTHING 🔥,” one stan gushed, while another dropped, “Mother of four slaying harder than my whole fitness app. Queen behavior.” Celeb squad’s all in too — Megan Thee Stallion reposted with a string of dumbbell emojis and “Get it sis, tour body’s about to EAT!,” and even Rihanna slid in a “Fenty glow on point, but that hustle? Iconic” via DMs, per insiders. TikTok’s already a frenzy: #CardiPostpartumGrind has 7 million views overnight, with duets of everyday moms mimicking her StairMaster strut in their living rooms, captioned “If Cardi can climb after Brim, I can climb out of bed.” One viral edit mashes her workout with “WAP” lyrics swapped for “Sweat, sweat, sweat” — pure gold, 1.5M likes and climbing.

But hold up — the backlash brigade rolled in quick, turning Cardi’s cardio confessional into a culture war. “It’s been DAYS, girl — rest for Brim!” one X user blasted in a thread that’s hit 20K retweets, tagging wellness influencers and OB-GYNs for backup. Another piled on: “This snap-back pressure is toxic AF. Not all of us have trainers and nannies.” The shade echoes the firestorm from her third kid’s arrival last fall, when she defended a week-old gym sesh against “insane industry expectations” accusations, clapping back, “This is my fourth — body knows the drill, and depression don’t play.” Experts are split: Dr. Michelle Henry, Cardi’s go-to derm who’s seen her through acne apocalypses, tells The Post it’s “empowering if cleared by docs — Cardi’s baseline is beast mode from years of touring.” But pelvic floor pro Caitlyn Tivy, DPT, warns via Parents mag, “Six weeks minimum for intense stuff, or risk prolapse city. Listen to your body, not the timeline.” Cardi’s response? A fiery X Spaces rant Friday night: “Y’all dragged me for gaining 20 pounds pregnant, now y’all ‘concerned’? Make it make sense. Brim’s napping, I’m moving — end of story.”

This glow-up grind fits Cardi’s MO: unfiltered, unapologetic, and always one step ahead of the narrative. Remember her 2021 Wave-era retinol rants, spilling tea on stretch marks and sleep regression like it was album therapy? Or that 2023 no-wig mirror flex, belting bars to her roots while hyping “wisdom wrinkles”? Post-Brim, it’s levelled up — the kid’s barely a week old (arrived November 10 via surrogate, per her low-key announcement), and she’s already teasing tour costumes that “hug the mama curves.” Sources say Diggs is all-in on the fam front, spotted pushing a custom Uppababy stroller through Foxboro parks while Cardi hits the treadmill, their May Met Gala smooches now a full-on power couple blueprint. Offset? Still lurking in the DMs drama from that “My kid lol” fiasco, but Cardi’s camp swears the workout’s her “mental armor” against ex-shade. “Stefon’s hyping her every rep — calls it ‘QB training for the stage,’” a pal dishes. No wonder her skin’s popping: that dewy vibe screams La Mer facials between feeds, with Garrette (her esthetician wizard) on speed dial for “post-placenta glow” tweaks.

The real tea? Cardi’s flipping the script on postpartum perfection. In a world where influencers hawk $2K waist trainers and “6-week shred” challenges, her StairMaster saga screams “real over reel.” She’s not chasing Offset’s ghost or Diggs’ spotlight — she’s chasing sanity, one step at a time. “Tour starts February, but Brim’s my forever opener,” she quipped in a follow-up Story, panning to the nursery where Kulture (7), Wave (4), and Blossom (wait, Brim’s the fourth — math on fleek) are napping in a pile of Fendi onesies. Fans clocked the subtle dig at co-parenting chaos, but mostly, they’re inspired: Pinterest “Cardi-inspired postpartum routines” searches spiked 250%, blending her cardio with yoga flows for “mama energy bursts.”

Haters gonna hate, but Cardi’s cardio comeback? It’s a masterclass in owning the mess. As she captioned a sweaty selfie: “Brim got the milk bar, I got the grind — we both winning.” With “Invasion of Privacy 2” whispers heating up and that Little Miss Drama tour looming (Palm Desert kickoff, anyone?), expect more sweat, more shade, more Cardi. Because if anyone’s turning baby weight into stage weight, it’s her. Bow down — or better yet, lace up.