I have the 2.25" kreitlers and have no problem ranging from ~100W to 400W keeping the bike at a comfortable speed (<50km/h) and with standard road gearing I don’t have to be doing much over 100rpm.
Recently added the headwind fan and this gets me a comfortable ~150W-600W without changing fan setting, the only struggle is anything that calls for >1000W as even with the fan open full the back wheel is all over the shop, though cadence is still manageable.
For reference, I’m ~70kg and keep my tyres at 90-100 PSI.