Garmin 265 for incorporating wellness metrics into Intervals.icu?

Apologies for the vague title, a little background:

34 y/o male and competitive endurance athlete since college. I recently (May 3) had a thoracotomy to remove the lower lobe of my left lung and I’ll be restarting chemo next week. My surgeon and oncologist gave me a Fitbit Charge5 to study how exercise can help prevent re-admittance to the hospital and help with the chemo. I’ve noticed the HR and sleep tracking with the fitbit is much more accurate than my Garmin 245, but I can’t pull the data into intervals.icu and I hate the idea of one device for workout gps tracking and one for wellness metrics.

That said,** have there been any hardware updates to the optical HR sensor on the Garmin 265 that would merit me upgrading from the 245?** I’m leaning toward Garmin because I’m already in the Garmin ecosystem with my bike computer and 245 for running/swimming. I’ve looked at Whoop, but that also doesn’t offer an API to pull the metrics into intervals.

Generally what I’d like to accomplish is m sleep, heart rate, vo2max, hrv etc with my workouts while I’m rebuilding aerobic capacity from the surgery and not overcook the effort as adjuvant chemo restarts.

It’s not that Whoop doesn’t offer an API, they Do. However, access to the API is restricted to Whoop Subscribers and there’s a monthly fee involved to be able to utilise the API.

I tried looking at integrating Whoop data thru its API for my BreakAway: Indoor Cycling App but then found that there are these conditions so had to abandon this project.

I’m not sure what the 265 offers above the 245 as the metrics you listed should already be supported by Garmin and can be pulled into Intervals.icu