Anybody remember the bodymedia fit armband from like 10ish years ago? Anything similar on the market

That may not be wrong. Of course we burn more calories at higher intensity, but the difference may not be that huge. For sure, sweat or being out of breath aren't reliable measures of calorie burn rate.

I've trained (sometimes) and worked out (always) with and for a short-endurance cardiovascular sport (on-water rowing, but some machine rowing as well). I've been doing that for over 20 years now.

A thing I've observed is what I'd call a "threshold effect". When I push the intensity, there's a point where it feels much harder, more fatiguing, triggers harder breathing, etc. . . . but my heart rate and the calorie expenditure are just increasing at a gradual rate over that time, not the dramatic change I'm feeling subjectively. (There are some physiological facts behind this effect, but I'm not going to belabor that here.)

The person above may be right about the Fitbit providing that. (I use a Garmin, and that doesn't integrate food tracking within its own sphere . . . but it does a great job with the training and sport-specific stats I need.)

If you want to get a full picture of calorie burn, I'd suggest a device you can wear 24x7 (except when charging, of course). You're burning calories when you're asleep, among other reasons.

If you link a supported device to MFP, you'll get some statistics about calorie consumption vs. calorie expenditure, but not exactly in the format you're describing. I'd say it's not as visual, but the info is there. There's a list of supported devices somewhere, but it includes the usual Fitbit, Garmin, Apple Watch, and more. The exact nature of how they integrate can be a little different from device to device, but you can ask questions here about that.

Yes, day and night, so it gives me also the details of sleep and heart (it has a button you can click to "obscure" it so it doesn't wake you with the light) and I use it also as alarm for the morning (it's weird, it only vibrates but strangely it's very efficient, and I find it very useful because it wakes only me and not my partner, as it doesn't produce noise). I keep it even in the shower, so in the meantime I wash it. Basically I didn't remove it since from December 2019, when I bought it (apart from when I weigh myself in the morning :-D). My model is an Inspire HR, very lean: obviously you see very little on the display of the watch itself (there are also big models, I thought of them but in the end I prefer a discreet device, and the price was also very different!), but both the app and the website are very rich (and they show also some different things, so it's useful having installed both).
PS: obviously I remove it also for charging, but it's a quick thing (apart from the first time that I remember loooong), about once every two-three days.

This is from my Fitbit. Note 1: as I said, I bought it at the end of 2019. I don't know if the current model features the same layout. Note 2: differently that in MFP, Fitbit updates burnt calories as the day goes on, so in the morning you'll be always over your budget because the BM is low.