Recently I started to have issues with my gravel bike, which I bought in April 2021, a Specialized Diverge Carbon Comp.
The first issue happens to be a clicking / creaking of the crankset when under load (same as in this video). I had this issue from the start and already brought the bike a couple of times to the mechanic, but it always just fixed the issue for half a week.
The second issues started to appear more recently. Every time I put the bike under load (e.g. driving uphill, linear driving or standing up), the back brake starts to rub. It only happens in higher gears (before not enough load). It is extremely annoying to hear and sometimes louder, sometimes less. And once it starts it does not stop for half a minute / minute, independent of the load.
I brought the bike to the mechanic who gave it back after a couple of days. He claims it is frame flex, but I have trouble believing this, as I did not have this issue from the start. Other people claim the caliper should be centered again, but I would have expected the mechanic to have done this. It is a really annoying sound, very loud and definitively not normal.
Does anyone have an idea what the issue might be? I would really appreciate any help / ideas where I can start looking, as the mechanic could not fix the issue and riding the bike like this (especially given the price) is not acceptable IMO.