You are making a wrong conclusion. This difference in the price of the coin in relation to USDC and USDT is due to the fact that the value of USDC is currently higher than the price of USDT. Accordingly, if the value of USDT is higher relative to the price of USDC, then the price of BTC in relation to these stablecoins will be the opposite of the situation described by you.
exactly this, for some reason, despite the promise of 1:1 peg offered by these stables, most of their value differ to each other, FDUSD is valued lesser than USDT, meanwhile right now USDT is valued lesser than USDC albeit not so much, but it shows that this small difference reflects the amount of trust people put into these stables, because recent news about USDT banning in EU, USDT has lost some small percentage of its value.
this difference also reflects on USDC and USDT pair to alts, so it's completely normal. but just feels kinda strange, aren't they supposed to be $1 . maybe just some liquidity problems i guess.