Isn't the corrected VO2 max trying to estimate the ability of the athlete? If so, that same athlete running at higher altitude will run slower, with probably a higher heart rate - particularly before they adapt to the altitude. Currently Runalyze is estimating about 44 corrected for me, (garmin fenix 5 gives about 53) running at sea level. When I go run up at about 6000ft (1800m) altitude, Runalyze corrected VO2 max drops to about 37, but garmin stays the same. I know this is only n=1 but https://pubmed.ncbi.nlm.nih.gov/16311764/
does look like altitude plays a large role. If runalyze is estimating race pace based on the corrected VO2 max, then if there's no elevation correction, it's only estimating for altitude at the same altitude as the training data - reasonable unless we're going to a race at a different altitude.