It doesn't make a difference, besides for speed and flexing your 10-pull.
It's not just a claim, it's literally written in the game that you will get a guaranteed 4 star every 10 pulls and a guaranteed 5 star every 90 pulls (character banner) or 80 pulls (weapon banner).
Here's the relevant text for the current limited banner:
5-Star Items For Event Wish - Sparkling Steps: Base probability of
winning 5-star character = 0.600%; consolidated probability (incl.
guarantee) = 1.600%; guaranteed to win 5-star character at least once
per 90 attempts.
4-Star Items For Event Wish - Sparkling Steps: Base probability of
winning 4-star item = 5.100%; base probability of winning 4-star
character = 2.550%, and base probability of winning 4-star weapon =
2.550%; consolidated probability (incl. guarantee) of winning 4-star item = 13.000%; guaranteed to win 4-star or above item at least once per 10 attempts.
There is no mention of 10-pulls - everything is counted per attempt and hence 10-pulls do not affect the guarantee nor odds.