I think Disney did fuck up the show, but just through the deal in general, not through any direct creative interference. Their refusal to say whether or not they were extending the deal until (presumably) after The War Between The Land And The Sea has aired really fucked up the rhythm of production, and has led to some indirect creative shenanigans (ie. pretty much forcing Ncuti Gatwa to leave because he needs to work, which forced a big rewrite to the end of S2 etc.)

Also if rumours are to be believed, the extra Disney budget didn't even help that much because they apparently insisted on everything being in 4K HDR, which ate up most of the time and budget anyway.