William Hartnell to Paul McGann are Doctors 1-8 in standard order. John Hurt is the 9th incarnation of the Doctor, but is called the War Doctor. Christopher Eccleston is the 10th incarnation, but called the ninth. David Tennant is the 11th, 12th, 16th and possibly co-17th incarnation, but is called 10 or 14. Matt Smith is the 13th incarnation. called the 11th. Peter Capaldi is the 14th (or possibly first of a new regeneration cycle), called 12. Jodie Whittaker is the 15th (or maybe 2nd new) incarnation, called the 13th. Ncuti Gatwa is the co-17th, or possibly third of the second set of Doctors, but is called the fifteenth.
Jo Martin is also some incarnation of the Doctor, but nobody (perhaps even including Chris Chibnall) knows what that’s about. Also the rest of the Timeless Child stuff makes this somehow even more of a clusterfuck, but I’m not even going near that one. Also the Curator exists in there somewhere.