To be consistently so good, over different kind of terrains, should be ringing some alarm bells.
What do the results of Remco's physiological tests tell us? Here’s an article that lists Remco’s V02 max at 85-87, his HT at 47-48, and his 10-20 minute power at 6.5-6.7 W/kg.
https://translate.google.com/translate?hl=en&sl=nl&u=https://www.sport.be/cycling/nl/nieuws/article.html?Article_ID=866481&prev=search&pto=aue
Let’s consider those values.
A V02max of 85-87 is high, in the range of what has been at times reported for Froome, but not an all-time high. Lemond and Indurain were reported to have values in the 90s, though we aren’t sure how reliable that information is. Bernal has claimed to have a value of 90 or more, and same with Gaudu. In any case, it’s pretty clear that at least a few athletes have had V02max values over 90. So Remco is not that exceptional in that regard. There are certainly other riders with values in that range who haven't been particularly successful. Oskar Svendsen reportedly recorded the highest V02 max of all time, 96.7:
https://cyclingtips.com/2019/06/wha...-tells-us-about-genetics-and-cycling-success/
V02max is important, but it's not everything.
His HT is higher than average, but again, not exceptional, as there are of course riders with natural HTs of over 50. It would contribute to his V02max, so it's really of less value than the latter. If anything, it suggests that some of the other contributory physiological factors, like intake volume, are also not exceptional.
His power is actually similar to what Pinot reported back in 2013: 6.9 W/kg for 10 minutes, and 6.4 for 20 minutes. Pinot also reported power of 5.9 W/kg for 45 minutes, which is more or less what would be regarded as FTP, or sustainable power.
https://www.fredericgrappe.com/wp-content/uploads/2015/03/pinot-ppr.pdf
That Remco might have a similar value for this period of time is suggested by his V02max. Assuming an efficiency of 22%, which is somewhat high, but quite plausible, and an FTP at 90% of maximum power, he would have an FTP of about 6.0 W/kg.
https://wattmatters.blog/home/2013/08/looking-under-hood.html
All this suggests his sustainable power could be close to what Pinot’s is, or was, which indicates that right now he has at least the potential to climb with some of the best. If you couple Pinot's climbing with world class TTng--at this point in time, maybe only Dennis is better--Remco does look formidable in any GT. An Indurain type rider, who at worst can limit losses on climbs and make up large chunks of time on TTs. The one other factor, which remains to be seen, is how well he can recover from day to day.
But then what separates him from Pinot? Right now, I'd say it's that, first, he's more explosive. Though I haven't seen any data, based on what he's doing on the road, I assume his power outputs in very short intervals, such as 30" or 1 minute, are very high, and that he reaches them very quickly, allowing him to make sudden attacks. And second, that he's of course a better TTer, allowing him to sustain those attacks on relatively flat or even lumpy terrain. If his power is no greater than Pinot's (they're about the same weight, maybe Pinot is slightly heavier, so their output in watts should be fairly similar), why is he a better TTer? Aside from perhaps better technique, there must be an aero advantage to his body type. In fact, that link I've posted comes to the same conclusion, claiming that he has an unusually low CdA, or surface area. This is the key to why larger riders are generally better TTers than climbers--power increases with mass, or the cube of body height, whereas surface area increases only with the square. So Remco, if the CdA claim is true, is able to hold surface area/mass down even as a relatively small rider, which otherwise would favor him only in climbs.
So how suspicious is he? If his FTP is no greater than 6.0 W/kg, then he's no more suspicious than Pinot, or some others in the peloton, at least when it comes to blood doping. Even skeptics like Ross Tucker would allow that values like this are possible clean. The highest suspicion in that regard comes with sustained, other-worldly climbs, and Remco hasn't produced any of those--yet. Of course, that doesn't mean he isn't blood doping, and there are other substances/programs that could be relevant to his explosiveness. I think it's also important to verify his CdA, because any time a rider with the FTP of elite climbers (if Remco proves that this is the case) is also able to TT at an elite level, one should be at least a little suspicious.