Right thinking, wrong conclusion. You should get one stud WR and then back up the truck on RBs the next few rounds.
In straight PPR, you're right that the crossover point tends to be around RB28 = WR42, e.g. in a 14-teamer, a low-end RB2 scores about the same as a low-end WR3. The difference - which you won't notice just looking at season-long totals - is that on a week-in, week-out basis the bottom drops out of RB scoring after that.
What I mean is that the list of WRs that consistently average 9-10ppg in PPR is reallllllly long, and you can get them well into the double-digit rounds. But if you look at the weekly scoring of the RBs who "totalled" that on the season (150-160 pts), most of them are part-season wonders ... starters who got hurt, or backups who stepped up. In 2018, Cook, Ingram, Michel, Doug Martin, Mike Davis, and Fournette all finished between RB30-40 - but few if any of them were drafted in that range. It's actually fairly difficult to find a consistent 9ppg at the RB position - a random sample of mid-round RBs on, say, Week 8 will find more of them scoring either 0ppg or 15ppg than 8-9.
Knowing that, you'll probably want to play 4RB/1WR in your format, which means you should gear your draft around landing one stud WR and then trying to land four starting RBs. That latter part won't be easy, and you'll need to throw a ton of early draft capital at it to make that happen. Thus my suggestion on strategy.