Yeah I think my steady state HR on a road or mountain bike on flats was mid 140's and that's if I'm pedaling my ass off. Definitely less taxing than running. On a run, ~175 bpm is my anaerobic threshold for race pace. I can maintain that for around 20 minutes before going balls out for the last minute to push 200 bpm if I'm hauling ass trying for a 5K PR. When I used to run more frequently, I could also sustain that HR for 10K and possibly longer (but with pace going down the longer the distance). On a regular training run, I do around 163 bpm average when I'm in good running shape, although it's a few bpm higher (at a slower pace) if I'm in generally good shape but haven't been focused on running. The better running shape I'm in, the lower my steady state HR is at a given pace and through training, you get very attuned to what 150, 160 170 bpm feels like and how long you can maintain that level of exertion.
Like you, combat sports and tactical situations were what motivated me to learn more about HR training. But it's always killed me that there's no practical HR monitor that will stay on during wrestling/boxing/Judo/BJJ sparring. Anecdotally, I feel like my average HR during intense rolls or competition is still well below the 170's I can sustain in a cardio session, but will be punctuated with brief spikes and might even be gunning it above 180 bpm when it's late in the match, your lungs are on fire and you're fighting for that last TD, reversal or escape. And yeah, my fine motor skills turn to dogshit as I approach max HR lol. If I'm required to do anything more complex than putting one foot in front of the other as fast as possible, I'm going to be a panic wrestler which for me is diving in for a shitty head and arm throw, hail mary drop knee seoi nage or sumi gaeshi all of which will be low % when I'm that spent.
But I'm convinced that outside of sport specific skills training, cardio training builds and maintains your cardio base which will lead to better performance when you're taxed as well as faster recovery. As you say, you want that 70% zone to be as high as possible.