The TUI system hasn’t been updated since March, so any flight that was due to be operated by an ACMI operator - and there were a few due to the Max grounding - will still show as being operated by an ACMI operator. The “confirmation” you received is just what the system is still telling either you or the staff member who confirmed it to you, if that’s the case.
When the U.K. government lifts the FCO advice against all but essential travel, and the company has finalised a revised schedule for the Summer - both of which are expected imminently - the system will be updated. You’ll almost certainly find that your flight times are changed either slightly or significantly and your flight will be on a TUI aircraft.
Not worth panicking over, and certainly not worth any members of the “press” on here getting their knickers in a twist over.