Revenue is skewed by on-field performance, but take away prize money (broadcasting revenue essentially) and Leeds are comfortably top 10 in terms of commercial and matchday income (based on the accounts released last spring and pertaining to 22-23 season), but only 19th for broadcasting/prize money (cos they finished 19th that season)
Their shirt sales placed them as the 16th biggest club in Europe (7th in the UK, above Celtic and Rangers but behind the rich 6) according to UEFA. That's pretty good going for a club without European football and who had recently spent 16 years outside the top flight
Their broader commercial income has them in 7th place in the football pyramid (again behind the rich 6), this is despite a terrible shirt sponsorship deal (signed before promotion in 2020 iirc)
As you point out, their crowds cannot be top 10 on account of stadium size, but despite this they still ranked 9th in England for matchday revenue, behind the rich 6 and W Ham and Newcastle (owing to their massive stadiums and extra games played in Europe and the cups). Interestingly though (to me), when you adjust for the number of games played, Leeds' £1.4m per game revenue is only 100k less than W Ham and 200k less than Newcastle, but still 9th overall. Brighton are the only other club in England whose stadium generates over £1m per game
Adjust for stadium size and Leeds are once again leading the chasing pack and in 7th place for matchday revenue, making £34.12 per punter, only about £3 less than Man City. That's £12 more per punter per game than a club like Villa, or £15 more than Everton, both huge, storied football clubs
Of course none of this matters much if you don't get it right on the pitch. Finishing 19th that season earned Leeds £111m in broadcasting payments. 10th place got £138m. That £27m difference equates to a season and a half of matchday revenue for some of the biggest names in English football